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Java Edition:Tutorials/Potentially Dangerous Versions

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Below is a list of versions that can corrupt or damage your world and versions that cause crashes. If the given version affects entities, blocks etc. in the way you wouldn't like to and still want to play on that version, keep them in unloaded chunks and remove them from your spawn chunks before updating.

Danger Definitions

Dangers Meaning
System Threat Harms or crashes the device running the game.
Hardlock Damages the world in a way that makes it unplayable. Crash loops may be fixed by updating.
Softlock Damages the world in a way that retains all data, but severely inhibits gameplay.
Chunk Corruption Damages the world by deleting or modifying chunks.
World Files Damages world settings or other miscellaneous world data, such as player inventories, maps, etc.
Crash Causes the game to crash once. See Hardlock for crash loops.
Performance Decreases the performance of the world.
Player Death Is able to kill the player in an unintended fashion.
Item Damage Damages items in the world.
Block Damage Damages blocks in the world, and/or discontinued block combinations.
Contraption Damage Damages contraption in the world, possibly irreversibly.
Entity Damage Damages entities in the world.

Classic

Version Issue Source Danger
Classic 0.0.21a The game will randomly freeze. After freezing, all progress since the world was loaded will not be saved. N/A Crash
Classic 0.24 Survival Test 03 Loading a world from previous versions will permanently corrupt the level.dat file. This means as soon as you quit the game, you won't be able to restore the map unless you have a backup. N/A World Files
Classic 0.27 Survival Test Classic 0.25_05 worlds cannot be updated to Classic 0.27 due to the serialVersionUUID of the Player$1 class not being set. This can be fixed by using the Classic 0.25_05 to Classic 0.27 converter. Both versions can be updated into Classic 0.28 and later without issue. Otherwise, the player must choose to play either Classic 0.25_05 or Classic 0.27 on their version path, they cannot play in both. N/A World Files

Indev

Version Issue Source Danger
Indev 0.31 20091223-0040 - Indev 0.31 20100110 These versions can not be saved. All progress made in these versions will be lost. N/A World Files
Indev 0.31 20100122 - Indev 20100223 Updating to these versions from classic will remove blocks from the edges and top of the world. The bottom of the world will be filled in with bedrock if there is a solid block above and lava if there is an air block above. N/A Block Damage
Indev 0.31 20100128-2310 - Indev 0.31 20100202-2330 Item entities fail to load from saves causing them to be deleted. N/A Item Damage
Indev 0.31 20100128-2304 - Indev 0.31 20100201-2227 In these versions the player has 64 inventory slots: the 1st to 36th within the usual inventory and 61st to 64th for equipment, when picking up items with all slots up to 36 taken the item will go into the 37th, effectively deleting it due to not being able to be accessed and the player not being able to respawn.

These are then properly deleted once upgrading into 20100202-2330 and beyond due to the inventory being reverted back to having only 40 slots.

N/A Item Damage

Infdev

Version Issue Source Danger
Infdev 20100227-1433 - Infdev 20100316 Opening containers such as furnaces and chests crashes the game. N/A Crash
Infdev 20100227-1414 - Infdev 20100325 These versions can not be saved. All progress made in these versions will be lost. N/A World Files
Infdev 20100313 Opening the player's inventory crashes the game. N/A Crash
Infdev 20100327 Block entities, such as chests and furnaces, do not save their contents unless the chunk they are in receives a block change (e.g. placing or breaking), potentially causing the loss of items. N/A Item Damage
Opening a lit furnace with no fuel after reloading it crashes the game. N/A Crash
Breaking blocks at build limit crashes the game. N/A Crash
Infdev 20100413 Placing torches, flowers, or saplings crashes the game. N/A Crash
Infdev 20100615 Water that has had block updates in previous versions will now randomly tick and flow, potentially breaking block combinations that have to do with invalid flowing liquids or invalid blocks next to fluids. This mechanic persists until 18w10c (a 1.13 snapshot). N/A Block Damage
Infdev 20100624 In this version, worlds were briefly saved using a new save format that made world files massive. The save format changes were reverted in the next version. These worlds cannot be recognized by any other version, and older worlds cannot be loaded in this version. Attempting to load these worlds in any version prior to 1.2.1 will regenerate the world, and versions after 1.2.1 will not be able to recognize the file at all. N/A World Files
Infdev 20100625-1917 Destroying a minecart crashes the game. N/A Crash
The game crashes when standing within 15 blocks of previously signs in this version. As the sign loads again after entering the world, this is a hardlock until updating to Infdev 20100627 or later. Additionally, the contents of the sign are deleted. N/A Hardlock
Infdev 20100624 - Beta 1.6.6 The removal of the infinite lava item and all cloth blocks results in a variety of crashes. Opening a container containing one of these will crash the game, and having one placed or as an item entity within render distance will make the world unplayable until their ID is recycled as another block ID. See Cloth Conversion for when these IDs are re-added to the game. N/A Crash + Hardlock

Alpha

Version Issue Source Danger
Alpha v1.0.1 - Alpha v1.2.0_02-launcher In these versions, placing a sign such that it gets destroyed or otherwise does not exist when editing GUI attempts to appear (e.g. placing it on the side of a cactus, or above build limit), causes a NullPointerException crash due to the sign not being found.

Before Alpha v1.0.5 this created a understacked sign.

N/A Crash
0.1.0 - 0.1.4 These alpha server versions do not save inventories or player data. N/A World Files
0.2.0 - 0.2.0_01 These alpha server versions are based upon Alpha 1.1.0 meaning obtaining a fishing rod in Alpha 1.1.1 to Alpha 1.1.2_01 will crash the server if dropped and picked back up, casting it or using it to mine blocks. N/A Hardlock
Rendering a fishing rod will crash Alpha 1.1.0 clients N/A Crash
Alpha v1.1.1 While this version does not cause any damage to your world, it can turn your entire computer screen gray, making it impossible to use your computer until it is rebooted. Depending on your graphics card, this version can turn your screen black or flash red extremely rapidly, potentially causing seizures. This was fixed in the very next version, Alpha v1.1.2. Launchers such as Betacraft, Codex-Ipsa, and MineOnline patch this issue. N/A System Threat
0.2.2 - 0.2.3 Going above build limit will freeze any client from Alpha 1.2.0 to Alpha 1.2.0_02, though still allowing them to interact with the world. N/A Softlock
Alpha v1.2.0 - Alpha v1.2.0_01 These Alpha versions do not drop the player's items upon death. N/A Item Damage
Alpha v1.2.3 Due to a bug with the newly implemented leaf decay, whenever a large amount of leaves attempt to decay this can cause a stackoverflow error. If in a heavily forested area this can hardlock the world. N/A Hardlock

Beta

Version Issue Source Danger
Beta 1.2 - Beta 1.5_01 Entering a nether portal whilst riding a boat, minecart or pig crashes the game and deletes the player's data. Minecraft Wiki Beta 1.5 Issues World Files + Crash
Beta 1.3 - Beta 1.7.3 Hovering over a IDV slab - A slab with a data value greater than 3 - in an inventory crashes the game.

These can be obtained via block transmutation.

N/A Crash
Beta 1.6 Test Build 3 - Beta 1.6.4 Attempting to shift-click items into a full container or into a full inventory will crash the game. Minecraft Wiki Beta 1.5 Issues Crash
Attempting to shift-click items into or out of a dispenser crashes the game, regardless of fill level. Minecraft Wiki Beta 1.5 Issues Crash
Beta 1.6 Test Build 3 Placing a map into your inventory on a server will cause a crash every time the player is ticked. N/A Hardlock
Beta 1.6 Shift clicking an item when your inventory is full causes the game to crash. N/A Crash
Beta 1.7 Right-clicking on a sheep crashes the game. N/A Crash
Pushing a sticky piston into the redstone line that powered the pushing piston crashes the game. If a piston pushes a redstone wire, the game will crash. N/A Crash
Beta 1.8 Pre-release Updating to this version will set the map features tag to 0, meaning no structures will ever spawn in your world again except dungeons. N/A World Files
Rendering any block with a biome tint in the nether hardlocks the game. Minecraft Wiki Beta 1.8pre Issues Hardlock
When furnaces placed in this version change state the game crashes. Minecraft Wiki Beta 1.8pre Issues Crash
Toggling Advance OpenGL after opening the game for the first time crashes. Minecraft Wiki Beta 1.8pre Issues Crash
Beta 1.8 Pre-release 2 ;) Attempting to shift-click an item into a full inventory will crash the game. Minecraft Wiki Beta 1.8pre2 Issues Crash
Attempting to shift-click items into or out of a dispenser crashes the game, regardless of fill level. Minecraft Wiki Beta 1.8pre2 Issues Crash
Beta 1.8 Pre-release - Beta 1.8.1 Dying from an arrow shot from a dispenser in multiplayer will crash the server. Minecraft Wiki Beta 1.8.1 Issues Crash
Setting a Mouse button as the inventory key crashes the game whenever it appears in a toast, this can happen in the achievement menu and the initial tutorial. N/A Hardlock
Beta 1.8 Pre-release - Beta 1.8 Pre-release 2 ;) Dying with XP in multiplayer in this version will duplicate XP, and the XP orbs will quickly start to lag the client and server. Minecraft Wiki Beta 1.8pre2 Issues Performance
Endermen can pick up any block, including bedrock and chests. If an enderman picks up a chest, the items inside it are deleted. Endermen are able to pick up any obtainable block until Beta 1.9 Prerelease 1. Minecraft Wiki Beta 1.8pre2 Issues Block Damage

1.0

Version Issue Source Danger
Beta 1.9 Prerelease - Beta 1.9 Prerelease 2 Dying from an arrow shot from a dispenser in multiplayer will crash the server. N/A Crash
Beta 1.9 Prerelease 1 - Beta 1.9 Prerelease 6 Setting a Mouse button as the inventory key crashes the game whenever it appears in a toast, this can happen in the achievement menu and the initial tutorial. N/A Hardlock
Beta 1.9 Prerelease 3-1 Hovering over certain debug items[1.0 note 1] will cause a crash, as they have not been assigned a name, and this version does not correctly handle nameless items. Additionally, the debug inventory present in this version contains one such item, the end portal block. N/A Crash
Attempting to shift-click an item into an enchanting table will cause the game to crash. N/A Crash
Beta 1.9 Prerelease 4 Breaking a Chest with enchanted items in it will cause the dropped items to lose their enchantments. N/A Item Damage
Beta 1.9 Prerelease 6 - 1.0.0 Attempting to pick block an end crystal crashes the game. N/A Crash

Notes

  1. ↑ The end portal block item, obtainable in this version, or piston head items and moving piston items (obtainable in previous versions) are known to trigger this crash. This likely applies to even more debug items, such as double slabs, and the currently unobtainable melon and pumpkin stems.[test]

1.1

Version Issue Source Danger
11w47a - 12w01a Attempting to pick block an end crystal crashes the game. N/A Crash
11w49a - 12w01a Clicking on achievements with the language set to Italian crashes the game. N/A Crash

1.2

Version Issue Source Danger
12w03a - 1.2.5 Liquids above world height can servely lag the game. N/A Performance
12w04a - 1.2.5 Dying to a fire charge shot from a dispenser - the initial damage and not the after-burn - crashes the server. N/A Crash
12w05a-1 Right clicking on a sitting tamed cat with a empty hand crashes the game. N/A Crash
12w07a Mobs spawning at build limit crashes the game. N/A Crash
12w07a - 12w07b Generating the End will generate a completely void dimension, with no blocks except for the obsidian platform (and an ender dragon). N/A Softlock
Attempting to place a sign above build limit crashes the game. N/A Crash
1.2.4 Rarely during chunk population features can generate in such a way that loads another chunk triggering it to populate, which crashes the game. This can be best seen when using the seed "Scotland". Minecraft Wiki 1.2.4 Issues Crash

1.3

Version Issue Source Danger
12w15a Attempting to pick block a piston head crashes the game Minecraft Wiki 12w15a Issues Crash
12w15a - 12w16a Changing the GUI scale crashes the game. Minecraft Wiki 12w16a Issues Crash
12w15a - 12w19a Dying to a fire charge shot from a dispenser - the initial damage and not the after-burn - crashes the server, as well in singleplayer in 12w18a and 12w19a. Minecraft Wiki 12w19a Issues Crash
12w17a - 12w23b Pick blocking a block while destroying it in creative mode crashes the game. N/A Crash
12w18a Entering the End does not initially load terrain requiring a relog but will still save the player's position meaning if the player does not exit quickly they can fall through the end platform and suffocate, or on some unlucky worlds fall into the void.

In generation where there is nothing below the platform an ender pearl or water bucket can be used.

Minecraft Wiki 12w18a Issues Player Death
12w21a Rendering the spawner animation freezes the game. N/A Hardlock
Dropping an item and reloading the world makes it unplayable until the item is picked up. If it is picked up instantly upon world load, the crash will not occur. N/A Hardlock
12w21a - 12w23b Any items in ender chests from these versions are deleted once updated into 12w24a or later, 12w24a is when ender chests were changed to save by player instead of by world. N/A Item Damage
12w23a Insta-mining any block crashes the game. Minecraft Wiki 12w23a Issues Crash
12w24a All items in ender chests are deleted after dying. Minecraft Wiki 12w24a Issues Item Damage

1.4

From 1.4.2, when crafting something that gives more than one item as an result (e.g. diamond blocks to diamonds, stairs, slabs) and not all resulting items fit into the inventory, the overflow gets deleted.

Version Issue Bug Report Danger
12w34a Item frames will consume an entire stack, but when broken will only return the one item, destroying the rest. N/A Item Damage
Casting a fishing rod into a nether portal crashes the game. Minecraft Wiki 12w34a Issues Crash
12w34b Attempting to zoom out a map in multiplayer, crashes the client. N/A Crash
12w38b - 12w39b There is an optimisation from in-20100213 to 13w24b, where if sound and music are both 0, the sound engine does not start at all. In these versions minecarts do not check if the sound engine exists when producing sound, meaning if both volumes are 0, and a minecart plays sound, it tries to access it, failing, and crashing the game. N/A Crash
12w40a - 12w41b Dispensing liquids into a solid block crashes the game. Minecraft Wiki 12w41b Issues Crash
12w40a - 12w42a Attempting to remove items from armor slots using number controls crashes the game. N/A Crash
12w41a-12w41b Dropping an anvil on an end crystal crashes the game. Minecraft Wiki 12w41b Issues Crash
Resizing the game window while in the anvil GUI crashes the game. Minecraft Wiki 12w41b Issues Crash
1.4.3 In this version, the particles created by iron golems when walking crashes the game. This can be avoided by setting particles to "Minimal". MC-1608 Crash
Player movement is canceled below Y-1 (Eye pos) stopping players from reaching the point where they take damage, as long as they fall at a reasonable speed, provided there is no available method to escape or die,[1.4 note 1] this is a hardlock. MC-1647 Hardlock
Breaking a previously saved jukebox will drop an air item and renders it, crashing the game. MC-1608 Crash
1.4.4 - 1.4.7 Breaking a previously saved jukebox will drop an air item, picking this up will crash the game. MC-2711 Crash
1.4.5 - 1.4.7 Destroying multiple chests at once sometimes causes crashes. MC-3339 Crash
12w49a In servers of this version, random blocks are shown client side in the end and nether, making it quite laggy and difficult to move around in those dimensions. These ghost blocks may be removed temporarily by forcing the server to send the proper data by right-clicking on them. MC-4200 Performance
12w50a Pressing Ctrl-Drop with no items selected crashes the game. MC-4537 Crash
12w50a - 1.4.7 Loading a chunk that contains an air item entity will regenerate the chunk. MC-2711 Chunk Corruption
12w50b - 1.4.6 Getting shot by a dispenser whilst wearing thorns crashes the server. MC-5246 Crash
1.4.6-pre Skeleton shooting the player crashes the game. MC-4896 Crash

Notes

  1. ↑ Since the player's entire hitbox is below y0, there is no way to escape using blocks, like water or ladders. Escaping may however be done via minecart, boat, other ridable mobs like a saddled pig, or enderpearl. In terms of dying, starvation does not work, since you do not use food while falling, so it must be another source of damage. As the most common place to fall into the void this way is the end, the enderdragon may be available to deal damage if it has not been killed. If there are spawnable blocks sufficiently close to the void, such as from an enderman farm, or low-down terrain from the end island, endermen could also be lured to fall off and deal damage as they fall past. Enderpearls may also be used to deal damage, even if there is nowhere to teleport to that would allow escape. These death-related methods of course do not apply on hardcore, but falling into the void without a way to escape is a hardlock in hardcore regardless of version.


1.5

When crafting something that gives more than one item as a result (e.g. diamond blocks to diamonds, stairs, slabs) and not all resulting items fit into the inventory, the overflow gets deleted.
From 1.5.1[test] pushing a locked chest onto a player's head crashes their game.[1.5 bug 1]
Redstone interaction with unobtainable-piston-blocks crashes the game.[1.5 bug 2]

Version Issue Source Danger
13w01a Breaking a chest or trapped chest whilst its open crashes the game or server. MC-5768 Crash
Creating a comparator subtract loop will hardlock the game. MC-5728 Hardlock
13w01a - 1.5.2 Loading a chunk that contains an air item entity will regenerate the chunk. MC-2711 Chunk Corruption
13w01a - 13w02b Breaking a previously saved jukebox will drop an air item, picking this up will crash the game and regenerate the chunks. MC-2711 Chunk Damage + Crash
13w02a Grass with data values over 2 (Green Shrub) cause a game crash when rendered. This also applies to many other blocks, such as invalid data value wheat and cocoa beans[test]. N/A Hardlock
13w02a - 13w02b Many unobtainable block items crash the game when rendered, such as Locked Chests[test]. MC-6757 Crash
13w02a - 13w09b Loading extreme data values of wheat (IDV Crops) crashes whenever loaded. MC-10503 Hardlock
13w02b - 13w05a Dropping an anvil on a redstone component crashes the game. MC-7094 Softlock
13w03a-2 Swapping to an empty hand crashes the game, this also happens when breaking a tool. MC-7622 Crash
13w03a If a minecart with hopper falls into the void, the game will crash. After that occurs, the game will not be able to load again in 13w03a, since attempting to rejoin the world will load the hopper minecart again. MC-7619 Hardlock
13w04a Trying to equip a helmet by clicking while looking at blocks will crash the game. MC-8189 Crash
13w05a-1, 13w05a-2 Destroying a jukebox with a disc inside crashes the game. MC-8775 Crash
Quickly breaking and then placing a sign and then exiting it, crashes the game. MC-8839 Crash
13w06a-1 Loading a chunk that contains a hopper minecart will crash the game. After that occurs, the game will not be able to load again in 13w06a-1, since attempting to rejoin the world will load the hopper minecart again. MC-9316 Hardlock
13w09a - 13w09c Exiting a rideable entity that you entered from another rideable entity crashes the game. MC-10312 Crash
2.0 In this version torches turn into burnt-out torches over time. This means when updating past 2.0, all the burnt out torches will be deleted, or if updated to 1.7-1.12, will be turned into acacia leaves. N/A Block Damage
If a 2.0 exclusive item is dropped on the ground and then updated to a version prior to 1.7.1, the chunk will be regenerated. MC-30940 Chunk Corruption
Droppers will only drop fish when activated, despite the item inside. This causes item loss, and could break redstone machines. N/A Item + Contraption Damage
In 2.0, the Redstone Bug is added. These spawn when redstone dust is deactivated and then reactivated. This could cause severe performance issues in worlds with a lot of redstone machines. N/A Performance
Furnaces have an increasing chance to explode when lit (often exploding after 1 item is smelted). This could destroy builds and redstone contraptions. N/A Block Damage

Bugs

  1. ↑ MC-12984. bugs.mojang.com.
  2. ↑ MC-68149. bugs.mojang.com.

1.6

When crafting something that gives more than one item as an result (e.g. diamond blocks to diamonds, stairs, slabs) and not all resulting items fit into the inventory, the overflow gets deleted.
From 1.6.2[test] the game crashes on pressing the inventory close key and an item manipulation key at the same time in large chests.[1.6 bugs 1]
Pushing a locked chest into a player's head crashes their game.[1.6 bugs 2]

Version Issue Source Danger
13w16a In multiplayer in this version, mounting a pig, horse, boat, or minecart will kick the player from the server. When logging back in, the player will be riding the entity again and will be kicked again, effectively banning the player from the server. The only ways to fix this are to delete the "riding" tag in players.dat or to update to 13w16b or later. MC-13628 Hardlock
Stone pressure plates no longer activate for players, possibly breaking some redstone contraptions. MC-13610 Block Damage
13w16a - 13w26a Binding "sneak" to any mouse button and trying to mount an entity crashes the game. MC-14126 Crash
13w16a - 1.6.4 Loading a chunk that contains an air item entity will regenerate the chunk. MC-2711 Chunk Corruption
13w18a Damaging a horse whilst riding it crashes the game. MC-15036 Hardlock
13w18a - 13w18b Destroying an item frame will crash the game. MC-15041 Crash
13w19a When armor breaks it deletes the selected item in the hotbar. MC-15416 Item Damage
13w21a In this version the game will crash frequently, not much is known about the cause of the crash but this version is mostly unplayable. MC-16353 Crash
1.6-1 Attempting to brew with awkward, mundane or thick potions hardlocks the game. MC-19061 Hardlock

Bugs

  1. ↑ MC-31222. bugs.mojang.com.
  2. ↑ MC-12984. bugs.mojang.com.


1.7

When crafting something that gives more than one item as an result (e.g. diamond blocks to diamonds, stairs, slabs) and not all resulting items fit into the inventory, the overflow gets deleted.
The game crashes on pressing the inventory close key and an item manipulation key at the same time in large chests.[bug 1]
Upon rendering a hopper with a data value greater than 5, the game will crash [test]. (Find bugref)
Updating the piston-extension block will crash the game, this block can be updated with R-Mouse, L-Mouse, and neighboring block changes[test]. (find bugref)

Version Issue Source Danger
13w36a - 13w36b Generating terrain at the world border hardlocks the game. MC-29493 Hardlock
13w36a - 13w39b Pushing a locked chest into a player's head crashes their game. MC-12984 Crash
13w36a - 1.7 Loading a chunk that contains an air item entity will regenerate the chunk. MC-2711 Chunk Corruption
13w37a - 1.7 (fixed in 1.7.1) The game will crash when an invalid ID item entity is loaded. This will also regenerate the chunk it is in. MC-30940 Crash + Chunk Corruption
13w38a Clicking the empty space next to the last button in the video settings crashes the game. MC-31641 Crash
13w38b Updating to this version will not corrupt your world, but loading a chunk containing a minecart will crash the game. This results in not being able to load the world again in 13w38b, since attempting to rejoin the world will load the minecart again. MC-31876 Hardlock
Destroying a nether portal block crashes the game. MC-31880 Crash
Generating new terrain in the nether sometimes[test] crashes the game. With some unfortunate timing one can even hardlock theirself. MC-31892 Hardlock
13w41a Entering an Ender Dragon, Giant, Ghast, Ghast Fireball, Magma Cube or Slime hitbox will crash the game, depending on the circumstances this may even hardlock the world. MC-34650 Hardlock

1.8

When crafting something that gives more than one item as an result (e.g. diamond blocks to diamonds, stairs, slabs) and not all resulting items fit into the inventory, the overflow gets deleted.
The game crashes on pressing the inventory close key and an item manipulation key at the same time in large chests.[bug 1]

Version Issue Source Danger
14w02a Updating redstone dust that updates tripwire crashes the game. N/A Crash
Updating the top half of a door crashes the game. MC-44338 Crash
Populating an empty chunk can crash the game due to structure and feature generation. This can hardlock a player in the End. N/A Hardlock
14w02a - 14w02c Right clicking a baby sheep, cow, or mooshroom with an empty hand causes a crash. MC-44848 Crash
14w03a In 14w03a, placing a flower pot will crash the game. MC-45004 Crash
14w04a In 14w04a, being hit by a mob in a world connected to via LAN would kick the player. MC-45496 Crash
14w05a If the player's head is inside a barrier block the game crashes. MC-46416 Hardlock
14w06a Placing a torch or redstone torch against an invalid block - I.e glass, slabs or chests etc. - in such a way that it needs to recalculate what it is attached to, crashes the game. MC-47560 Crash
14w06a - 16w42a (a 1.11 snapshot) Riding a vehicle (e.g. boat, minecart, horse, donkey, mule, etc) and logging out on either a world that has been opened to LAN or on a dedicated server will delete the ridden entity. MC-47508 Entity Damage
14w10b In 14w10a, player data was changed to use UUID instead of username. In 14w10a, username-based player data automatically converted to the new UUID-based system, but in 14w10b, this process was faulty, resulting in having a complete, but not usable <username>.dat, along with a blank <UUID>.dat, which is used. If your world is loaded in this version, your player data will not be deleted or corrupted, but will not be usable without editing file names. N/A World Files
14w11a - 14w21b Rendering a IDV sapling (DV6 or higher) will crash the game, if placed in a hotbar or existing as an entity nearby, this will hardlock the player. N/A Hardlock
14w18a Rendering an item frame crashes the game. This results in not being able to load the world in 14w18a anymore, since attempting to rejoin the world will load the item frame again. MC-54008 Hardlock
14w25a Placing a ladder on the ground next to a block you can place a ladder on crashes the game. MC-57234 Crash
Placing logs crashes the game. MC-56893 Crash
Damaging a guardian with a splash potion of instant damage crashes the game. MC-57112 Crash
14w25a - 14w25b Loading a DV 0 chest will crash the game. MC-57470 Hardlock
Loading invalid data value log2s and leaves2s crashes the game. This probably also applies to subsequent versions. N/A Crash
14w26a - 14w26b Updating to these versions causes some blocks in your world to be corrupted, which will be deleted in 14w26c. MC-59294 Chunk Corruption
14w26c From this version until 19w37a (1.15 snapshot), DV 0 chests will be deleted upon loading or world optimization. MC-123686 Block Damage
14w27a Updating to this version does not directly corrupt your world. However, loading a chunk that contains a minecart chest will crash the game. After that occurs, the game will not be able to load again in 14w27a, since attempting to rejoin the world will load the minecart again. MC-59972 Hardlock
14w27b Loading a stronghold will crash the game. Once you enter the location of a stronghold it will crash, and reopening the world will continue to crash the game, until the stronghold is completely loaded. MC-60556 Crash
Breaking double tall flowers can occasionally crash the game. MC-60707 Crash
14w28a When a plant receives a random tick, the game will crash. The only way to avoid this is to either set the gamerule randomTickSpeed to 0, which will also prevent plants from growing, or to have no plants within render distance to be randomly ticked. MC-61059 Softlock
Right clicking with an empty bucket leads to a crash. MC-61093 Crash
Viewing attached tripwire in F3 crashes the game. MC-61107 Crash
Moving a block with a data value greater than 5 or stone with a data value greater than 0 crashes the game and deletes the block. MC-61371 MC-61372 Crash + Block Damage
Creating a double wooden slab crashes the game. MC-61082 Crash
Placing a ladder crashes the game. MC-61066 Crash
14w28b - 1.8.3 Putting a No NBT Spawn Egg in a mob spawner crashes the game. MC-61895 Crash
14w30c Opening Snooper Settings crashes the game. MC-63507 Crash
14w30c - 14w31a Breaking a door while a villager is interacting with it crashes the game. MC-64727 Crash
14w32a Attempting to pick block red sandstone slab will crash the game. MC-65512 Crash
14w33a Attempting to place a torch or redstone torch on the underside of an invalid block - I.e glass, slabs or chests etc. - in such a way that it needs to recalculate what it is attached to, crashes the game. MC-MC-66983 Crash
14w34a Furnaces delete any items newly placed inside (old furnaces will retain their contents), and a hopper attempting to place items or fuel inside a furnace with empty slots for their respective item type will crash the game. MC-64727 Item Damage + Crash + Softlock
Going above 256 or into the void crashes the game. If poorly timed this may hardlock the player MC-67974 Hardlock
1.8-pre1 Fire charge colliding with any living entity crashes the game. If unfortunate this may lead to a hardlock MC-68748 Hardlock
1.8.2-pre2 Creepers, Blazes, Pigs, Ocelots, Rabbits, and Iron Golem will experience suffocation damage when standing on full, solid blocks MC-76556 Entity Damage
1.8.2-pre3 Hoppers do not transfer items between inventories. MC-76562 Contraption Damage
1.8.2-pre5 Inserting a music disc into a jukebox crashes the game. MC-77030 Crash
1.8.2 Under certain circumstances, thrown ender pearls can regenerate the chunk they are in when loaded from disk. N/A Chunk Corruption
Throwing an ender pearl through a Nether portal crashes the game. N/A Crash
15w14a Every Carrot on a Stick items are deleted from the world. N/A Item Damage
All zombies spawn with the ability to pick up items and skeletons constantly drop bone meal. This means that zombies can easily pick up the bonemeal and never despawn. Bonemeal item entities over time will also decrease performance. N/A Performance
The Poison effect gets deleted from all loaded entities. N/A Entity Damage

1.9

When crafting something that gives more than one item as an result (e.g. diamond blocks to diamonds, stairs, slabs) and not all resulting items fit into the inventory, the overflow gets deleted.
The game crashes on pressing the inventory close key and an item manipulation key at the same time in large chests.[bug 1]

Version Issue Source Danger
15w31a Updating to this version will alter any signs. Each time a sign is reloaded (if just on relog or upon chunk reload) it will gain more characters (specify the equation for character growth). Eventually, after the sign reaches somewhere around 65,535[test] characters, loading the sign will crash the game, and can essentially force the player to no longer be able to enter the world until unknown version[test]. MC-83187 Block Damage + Hardlock
15w31a - 15w32a Attempting to join a server on this version will kick the client with a MalformedJSONException. MC-82968 Softlock
15w32a Shooting the ender dragon with a bow crashes the game. MC-85110 Crash
15w32b When playing in this version, it is possible for entities not within spawn chunks but within render distance of spawn to be deleted, unless in minecarts. MC-85285 Entity Damage
15w33a - 15w40a Tamed cats from before 1.8.8 (not 1.8.9) regenerate the chunk they were in. MC-89699 Chunk Corruption
15w33c Breaking a skull causes a crash. MC-86137 Crash
15w35a Zombies spawned in this snapshot will have no AI, so they will not take up the mob cap. MC-87193 Performance
15w35a - 15w35b Doors will turn into half doors upon the chunk being loaded. MC-87196 Block Damage
15w35c Punching a wolf crashes the game. MC-87563 Crash
Using a carrot on a stick while on a pig crashes the game. MC-87567 Crash
Killing a named silverfish crashes the game. MC-87569 Crash
15w35c - 15w35e Rendering a wolf or ocelot spawner crash the game. This can lead to a hardlock if pre-existing MC-87759 Hardlock
15w36a Stepping off a pressure plate crashes the game. MC-87869 Crash
15w36a - 15w36b Looking at an Enderman crashes the game. MC-87881 Crash
15w37a Going outside of height limit or into the void with F3 open crashes the game. MC-88357 Crash
The game will crash when crafting an empty shield with a banner. MC-88377 Crash
15w37a - 15w51b Every hopper minecart placed before 15w37a no longer pick up items. (Enabled:0b). MC-88668 Entity + Contraption Damage
15w38b Shift clicking into a full container deletes the items. MC-88929 Item Damage
15w39a - 15w39c Hopper minecarts and chest minecarts that have duplicate UUIDs cause their contents to explode upon loading the chunks while still containing the items, effectively working as a duplication method. However, this over time could cause a lot of tick lag in heavily traversed chunks with mineshafts or player placed minecart chests/hoppers. This could also break certain redstone contraptions. MC-89602 Performance + Contraption Damage
15w40a It is not possible to connect to servers. MC-89643 Softlock
15w41a - 20w22a (a 1.16 snapshot) Passengers that are saved in a different chunk than their mount will be deleted. MC-136760 Entity Damage
15w42a - 15w44b Multiplayer servers crash when breaking frosted_ice with silk touch. In singleplayer, this produces a air item. MC-90578 Crash
15w44a When combining and/or renaming a item in an anvil, clicking the item out of the output slot would delete the item. This can be avoided by shift clicking. MC-91521 Item Damage
15w44b - 1.9-pre2 When updating a 1.7 or older world to versions within this range, signs will only use the first word of each line, and books only use 1 word. MC-92525 Block + Item Damage
15w46a Minecart unloaders (Comparator related bug) causes a crash loop. MC-92588 Crash
Redstone blocks emit power through blocks (Potentially breaking redstone machines). MC-92562 Contraption Damage
15w49a Client crashes when fully depleting an item stack. MC-93592 Crash
15w49b If a fireball hits an entity, the game crashes. MC-93655 Crash + Softlock
16w02a Game crashes when load/unload beacon MC-95541 Hardlock

1.10

When crafting something that gives more than one item as an result (e.g. diamond blocks to diamonds, stairs, slabs) and not all resulting items fit into the inventory, the overflow gets deleted.
The game crashes on pressing the inventory close key and an item manipulation key at the same time in large chests.[bug 1]

Version Issue Source Danger
1.10 If a player does not load the central end island in a world session, the DragonFight tag will be erased. This has a few side effects:
  • The Gateways list will regenerate. Whenever a dragon dies again, they will be regenerated in the order they were first created.
  • The ExitPortalLocation will be recalculated[1.10 note 1] when an end crystal is next placed.
  • The dragon will be marked as killed, but legacy dragon fight detection will restore if a dragon is alive immediately upon the end reloading.
  • The dragon unique UUID will be erased, but will be restored if a live dragon is found. This changes whenever a new dragon is summoned anyways.

The ExitPortalLocation recalculation may lead to a softlock, if the resulting y value is -2, as this leads to no end portals being placed. [1.10 bug 1]

MC-103497 World Files + Softlock

Notes

  1. ↑ The method that determines the new ExitPortalLocation will take the following steps:
    1. Find the highest solid or liquid block at 0,0, and subtract 1 from the Y position.
    2. If the block at that location is bedrock, and the Y level is greater than 63, subtract 1 from the Y position.
    3. Repeat step 2 until the condition is no longer met.
    Notably if there are no blocks at 0,0 this results in the Y level being -2. As a result of the exit portal location being changed, one must place the end crystals at the new portal location rather than the physical portal to resummon the dragon, often requiring the use of bedrock breaking to remove an old portal that is in the way.

Bugs

  1. ↑ MC-93185. bugs.mojang.com.

1.11

The game crashes on pressing the inventory close key and an item manipulation key at the same time in large chests.[bug 1]

Version Issue Source Danger
16w32a When crafting something that gives more than one item as an result (e.g. diamond blocks to diamonds, stairs, slabs) and not all resulting items fit into the inventory, the overflow gets deleted. N/A Item Damage
Attempting to ride a donkey causes the game to crash. MC-105956 Crash
Casting a fishing rod into a nether portal and reeling it in causes the game to crash. MC-106014 Crash
Dispensing a pumpkin or a wither skull without spawning iron golem or wither crashes the game. MC-106036 Crash
16w32a - 16w35a Upgrading into these versions deletes all mob kills and killed by statistics, this is due to the entity ID format changes[1.11 note 1], and without a datafixer to convert it, this causes the old statistics to be unrecognised, and subsequently deleted. MC-106314 World Files
Upgrading into these versions deletes specific passengers,[1.11 note 2] this is due to the entity ID format changes,[1.11 note 1] and without a datafixer to convert it, this causes the passengers to be unrecognised, and subsequently deleted. MC-106084 Entity Damage
16w32a - 1.11-pre1 Upgrading into these versions deletes spawner minecarts this is due to the entity ID format changes,[1.11 note 1] and without a datafixer to convert it, this causes it to be unrecognised, and subsequently deleted. N/A Entity Damage
16w39a Inserting fuel into furnace crashes the game. If a hopper inserts fuel this can hardlock you. MC-107392 Hardlock
Placing a shulker box into non full blocks with metadata, e.g. signs, extended pistons, or flowers, crashes the game. MC-107501 Crash
Llamas fail to save inventory NBT data, causing a crash when interacting with a Llama after reloading the world. MC-107536 Item Damage + Crash
Strength value of 0 llamas - llamas that are unable to hold a chest, which are only obtainable via spawn eggs and /summon - crash the game when attempting to breed. MC-107683 Crash
16w41a Viewing any negative durability item crashes the game, if in hotbar this can softlock the player. MC-108729 Hardlock
16w43a Casting a fishing rod directly up or down crashes the server. MC-109256 Crash

Notes

  1. ↑ 1.0 1.1 1.2 Entity IDs were converted from UpperCamelCase into lower_snake_case and some were slightly renamed
  2. ↑ Armor Stand, Cave Spider, Horse (Donkey, Mule, Skeleton Horse & Zombie Horse) Iron Golem, Ocelot, Magma Cube, Mooshroom, Polar Bear and Zombie Pigmen.

1.12

Up to 1.12.2 the game crashes on pressing the inventory close key and an item manipulation key at the same time in large chests.[bug 1]
Also to note, throughout 1.12 snapshots there are many recipe book item deletion methods.

Version Issue Source Danger
17w13a The game crashes when trying to use crafting book and items needed are in off-hand or armor slots. MC-114936 Crash
17w13a - 17w13b Items in the crafting table disappear when selecting a recipe. MC-114943 Item Damage
The game crashes when cancelling or changing the recipe in the recipe book with a full inventory. MC-115204 Crash
17w14a - 17w15a The client crashes when using the new shift-click recipe book feature in a server. MC-115528 Crash
17w15a Right clicking on the underside of a block with a torch crashes the game. MC-115807 Crash
17w16a The game crashes when changing dimension or relogging with a full inventory. MC-116398 Crash
17w16b - 17w17b Placing a torch on a wall with a fence gate underneath causes the game to crash. MC-116515 Crash
17w17a relogging whilst respawning the ender dragon causes the game to crash. MC-116656 Hardlock
17w17b Attempting to place a snow layer on top of a fence gate crashes the game. MC-116931 Crash
1.12-pre1 The game crashes when attempting to craft using the 2x2 crafting grid without first opening recipe book. MC-117211 Crash
1.12-pre3 The recipe book crashes the game upon selecting a previously used recipe without closing the GUI. MC-117560 Crash
The game crashes when clicking on dispenser recipe and attempting to craft a dispenser using an enchanted bow. MC-117563 Crash
The game crashes when you open the advancements window while no advancements have been complete. MC-117564 Crash

1.13

1.13 versions and onwards have a high chance of regenerating chunks, especially with very old worlds.

There are also countless crashes and saving issues not mentioned here during development versions.

Various blocks do not update correctly throughout the 1.13 snapshots, including stairs, redstone, glass panes, iron bars, walls, fences etc.[1.13 bug 1][1.13 bug 2][1.13 bug 3]

Version Issue Source Danger
17w45b - 18w14b Flying directly up kicks the player (e.g. with an elytra). MC-122354 Softlock
17w47a Entity statistics do not exist, meaning that updating to this snapshot will delete all entity specific statistics. N/A World Files
17w47a - 17w47b Killing a creeper with a skeleton's arrow as to drop a music disc, crashes the game. MC-122373 Crash
17w47a - 17w49b Container changes don't update nearby hoppers, potentially breaking redstone machines. MC-122159 Block Damage
17w47a - 1.13 The unstable blockstate for TNT is missing. Loading any unstable TNT in these versions will convert it into normal TNT. MC-122563 Block Damage
17w47b All updated spawn eggs are removed. N/A Item Damage
Player is kicked from multiplayer when opening a chest or shulker. MC-122347 Crash
17w48a Crash relating to sticky pistons and carpet built in a particular formation. MC-122573 Crash
17w47b - 18w03a The game crashes when a player dies from a player damage source (e.g. shot arrow, lit TNT, splash potions). MC-122883 Crash
17w49b Pistons lose their piston head when pushing the block that powers it, potentially breaking redstone machines. MC-122987 Block Damage
18w01a Server crashes when an item frame with a map is loaded, and no player has that map in their inventory. MC-123771 Hardlock
18w01a - 1.13 pre2 Terracotta, spawn egg and entity statistics are deleted. MC-124025 World Files
18w06a Game crashes when generating snow biomes. MC-124903 Crash
Game crashes when opening furnace recipe book. MC-124930 Crash
18w06a-18w22c Opening a superflat world with the ocean monuments tag makes the world unopenable. MC-124972 Hardlock
18w06a - 1.13.1 Structures can generate past height limit crashing the game and possibly causing a hardlock. MC-136526 Hardlock
18w06a - 18w07c Game crashes when generating a mansion. MC-125124 Crash
18w06a - 18w19b Command block minecarts vanish upon reloading a world. MC-124998 Entity Damage
18w08b Can potentially update blocks on chunk borders, potentially destroying discontinued block combinations in nether after updating from 1.12.2. Didn't manage to replicate[test].

Video reference: https://youtu.be/NvZ8J05w3iU

N/A Block Damage
18w08b - 18w14b Fish unrestricted spawning causing world to inevitably crash from the number of entities. MC-126185 Performance
18w10d Big chests are split into small chests. MC-126559 Block Damage
18w11a - 18w14a In these versions, drowned cause a ticking entity crash. Re-joining the world will load the drowned again, making it impossible to play the world again in either of these versions. MC-127242 Hardlock
18w19a Loading a world from a previous version will completely reset all chunks in the world, deleting all builds, entities, structures, and blocks. Downgrading will not fix the world, meaning there is no way to recover anything without loading a backup. N/A Chunk Corruption
When putting an item with NBT tag (Potions, Tipped arrows, Enchanted books, written books and maps) in an anvil crashes the game. MC-129221 Crash
18w19b - 18w20b Game crashes when loading a chunk with a player head in a chest. MC-129517 Softlock
18w20a Loading a world in 18w20a deletes command block NBT. MC-129615 Block Damage
18w21a - 18w21b Dolphins spawn infinitely outside of despawn radius. MC-130197 Performance
18w21b - 18w22a Named items stored in containers and nametagged mobs do not have their names updated correctly. MC-130345 Item + Entity Damage
All maps become "Map #0" when updating from 1.12.2. MC-130400 Item Damage
18w22a Item frame drops when you load a world from 1.12.2. MC-130422 Entity Damage
Stack overflow error when opening an 18w21b world in 18w22a. MC-130424 Softlock
18w22b - 18w22c Updating to this version will convert all enchanted books, including those in villager trades, will have their enchantments converted to Protection. The books will have enchantment levels and number of enchantments preserved, meaning that books can be obtained with Protection V or multiple Protection enchantments. MC-130489 Item Damage
18w30b Placing or dispensing wither skeleton skull crashes the game. MC-134967 Crash
1.13-pre3 As part of the 1.13 Flattening, enchantments were changed from using a numeric enchantment tag to using a word-based enchantment tag. 1.13 automatically converts the numeric tag to the word based tag, but due to a bug in 1.13-pre3, any enchanted book, including those in villager trades, updated directly from any version from 12w49a-18w20c will not convert, even in later versions. Numeric tags are not readable in 1.13+, leading to the enchantments on these books being lost. N/A Item Damage
1.13-pre5 New entity IDs caused many entities to disappear and some statistics/advancements related to these entities. MC-132320 World Files
1.13-pre9 Due to an issue with the mob spawning algorithm, the player would instantly crash in the end, hardlocking them. MC-133653 Hardlock
1.13.1 - 1.13.2-pre2 ⇧ Shift-right-clicking on a shulker box using bone meal causes the game to crash. MC-136888 Crash

Bugs

  1. ↑ MC-123136. bugs.mojang.com.
  2. ↑ MC-125625. bugs.mojang.com.
  3. ↑ MC-130140. bugs.mojang.com.

1.14

19w05a to 1.14-pre5 Reloading chunks with a sign having over 65535 characters softlocks the game during reloading process.

Version Issue Source Danger
18w43a Opening the F3 menu for a second time will crash the game. MC-137474 Crash
18w44a - 18w49a If a player entity is inside of a chunk when it first loads (such as when logging in or teleporting into unloaded chunks), all block entities within that chunk will lose their data. MC-138938 Chunk Corruption
18w44a - 19w02a Terrain that was last saved before release 1.13[test] will have new world generation occur, which will overwrite any blocks that existed where generation occurred. MC-137961 MC-138547 Chunk Corruption
18w44a - 19w07a When a wolf damages baby polar bears the game crashes. MC-138699 Crash
18w44a - 19w11b[test] Entities may randomly duplicate. These entities will have duplicate UUIDs. Duplicate UUID mobs are automatically removed by the game upon loading in 1.14 Pre-Release 5 and above. MC-138871 Performance
18w44a - 1.14.2 Pre-Release 2 Entities on chunk borders will be deleted when the world is reloaded. This can result in the loss of villagers, item frames, armor stands, animals, nametagged mobs, etc. MC-150170 Entity Damage
18w46a - 18w47b The game crashes if scaffolding falls onto a shulker box. MC-139378 Crash
19w04a - 19w04b Reloading chunks with a sign having over 65535 characters crashes the game. N/A Hardlock
19w12a In this version, loading a chunk containing an active conduit will crash, and creating a hardlock. MC-146246 Hardlock
19w12b The respawn position is incorrectly calculated to always be obstructed, sending the player back to world spawn and deleting their spawn point. MC-146381 Entity Damage
19w13a In this version, villager breeding will crash the game. MC-146783 Crash
1.14 Pre-Release 4 - 1.14 Villagers that have zero experience will lose their trades upon loading in these versions. Trading with the villager at least once in any version from 19w11a to 1.14 Pre-Release 3 will prevent this from occurring. MC-148923 Entity Damage
1.14.1 Pre-Release 1 - 26.1 Snapshot 3 (present) Villagers that have zero experience and either have less than 4 trades unlocked or have not unlocked tier 2 1.8 - 1.13 era trades will lose their trades when loaded in 1.14.1 Pre-Release 1 and any version beyond. Trading with the villager at least once in any version from 19w11a to 1.14 Pre-Release 3 will prevent this from occurring. N/A Entity Damage
1.14.3 Pre-Release 3 Attempting to place or enter a chunk with a item frame, crashes the game and or the server (if placed in spawn chunks) MC-151185 Crash
Upgrading a world into this server version will delete all item frames within the spawn chunks. MC-154499 Crash

1.15

Version Issue Source Danger
19w35a - 19w36a The game crashes when trying to render entities inside slime or magma cube spawners. MC-160248 Hardlock
19w36a Updating to this version will set the following game rules to false:
  • drowningDamage
  • fallDamage
  • fireDamage
  • doInsomnia

These gamerules being set to false means the player will no longer take any damage from drowning, falling, fire or lava, and no phantoms will spawn. These gamerules cannot be set back to true without commands.

MC-160464 World Files
19w38a Game crashes when breaking blocks. MC-161268 Crash
19w39a Game crashes when player model is rendered after the player is stung by a bee. MC-161882 Crash
1.15 Pre-release 1 Getting within 16 blocks of an end gateway hardlocks the player. MC-166004 Hardlock

1.16

Version Issue Source Danger
20w06a - 20w10a The way comparators calculate their signal strength changed. Before, comparators prioritized reading a container unless the power level of the block behind them was 15. In these snapshots, they take the highest value between reading a container and reading the power level of the block behind them, which results in some redstone contraptions breaking. MC-171079 Contraption Damage
20w07a All upgraded villagers will disappear. MC-172078 Entity Damage
20w13a In this version, dying without a bed or respawn anchor will prevent you from moving or interacting with the world after respawn, soft locking you until you update to 20w13b or later. MC-176227 Softlock
20w14∞ 20w14∞ is an April Fool's snapshot that adds the ability to travel to many randomly generated dimensions. Some of these dimensions will crash the game, leading to the player not being able to leave the dimension. N/A Hardlock
20w20b - 20w21a Opening your world in either of these versions will clear the end gateways list in level.dat, preventing any new end gateways from generating, even in later versions.[99] If your world is loaded in one of these versions, any of the 20 end gateways not generated prior to loading in these versions will never generate. MC-184482 World Files
20w21a Any structures generated in previous versions will not be considered valid, causing mobs to no longer spawn there. MC-184740 World Files
1.16-pre1 In this version, world generation settings are not saved, causing weird chunk errors and borders. Dimension settings are also removed from level.dat, disabling the Nether and End dimensions permanently, in this version and in future versions, unless level.dat is restored to a state in which these settings are present. Worlds created in this version will not work properly in any future versions without world save insertion, and if saved in the Nether or End during the initial session, the world becomes permanently inaccessible. MC-187358 Hardlock
1.16-pre3 Game crash when dispensing a shulker box. After reloading the world, the shulker box will be placed and in the dispenser. MC-188451 Crash
20w27a If a piglin or piglin brute zombifies in the overworld or end, the world crashes. MC-193073 Crash
20w28a Structure data of pillager outposts, villages, and bastion remnants get lost when updating a world to 20w28a. MC-194300 World Files
20w28a - 20w29a This version changes the Nether biome map to what they should be according to the seed, overwriting biome maps that were generated in earlier snapshots. MC-194273 World Files
1.16.2-pre2 - 1.16.2-pre3 Creating a superflat world without selecting a preset crashes the game and makes the world unusable due to the biome being set to "null". MC-197197 Crash

1.17

WARNING, playing on 21w06a to 21w14a will prevent you playing the remaining 1.17 versions.
This is due to these versions having a different world height that was reverted in 21w15a. The world can be upgraded to 1.18 versions.

Version Issue Source Danger
21w03a - 21w19a Updating to this version on a world from before 18w21a will not convert the enchantments to the new format. N/A Item Damage
21w05a In this version, the game will randomly freeze and crash and the use key causes a lot of lag issues. MC-214233 Crash
Copper blocks from previous versions are incorrectly updated. Some blocks disappear, and the fully weathered copper blocks revert into the penultimate weathered block stage. MC-213802 Block Damage
21w18a - 21w19a Dying in nether portal causes a soft lock, where player can't respawn. Updating fixes the issue. MC-225253 Hardlock
21w20a - 1.17 Pre-release 1 Slimes and magma cubes do not target entities, the iron golem and the player possibly breaking farms. MC-225911 Contraption Damage

1.18

Version Issue Source Danger
1.18-exp7 Forceloading world to this version deletes all spawners' data and makes them pig spawners. N/A Block Damage
21w37a Forceloading older worlds into this version either crashes game, or deletes all chunks. N/A Chunk Corruption
21w37a - 21w40a Worlds created with seed REDApRES or any other seed equating to 0 crash upon loading new 1.18 biomes. MC-237330 Softlock
21w39a - 21w42a Upgrading to any of these versions will prevent caves from generating below previously generated terrain. N/A Block Damage
21w43a Upgrading from ≤1.11.2 to this version doesn't properly update many block states, leading to breaking some builds or even destroying some discontinued block combinations. MC-239856 MC-239899 Block Damage
22w06a Opening the beacon GUI in this snapshot will crash the game. MC-248523 Crash

1.19

Version Issue Source Danger
22w13a Generating a structure with an allay (usually a pillager outpost or a woodland mansion) will crash the game. After that occurs, the game will not be able to load again in 22w13a, creating a hardlock. MC-249712 Hardlock
22w13oneBlockAtATime Contents of dispensers and droppers are lost. N/A Item Damage
Item entities are removed. N/A Item Damage
All items in villager trades are converted to air. N/A Entity Damage
22w16a Opening singleplayer will crash if there is an Alpha format (Infdev 20100327 - Beta 1.2_01) world in the saves folder. MC-250312 Crash
22w16a - 22w16b Rarely bee's pathfinding can crash the game. MC-250321 Crash

1.20

Version Issue Source Danger
1.20 Pre-release 1 torchflower_crop causes the game to crash when pollinated by bees and hardlocks the world. MC-262508 Hardlock
23w31a - 23w33a Loading the world in these versions deletes the Absorption effect MC-264698 Entity Damage
23w32a - 23w33a Updating to these versions from 23w31a or earlier deletes all effects MC-264750 Entity Damage
1.20.3 Pre-release 1 Any minecraft:grass items will be deleted, unless they are stored within bundles. The related statistics will also be deleted. MC-266890 Item Damage
1.20.3 Decorated pots can delete items stored in them when reloading the world. MC-267185 Item Damage
24w03a - 24w03b Shooting a breeze with a piercing crossbow causes the game to crash. MC-267937 Crash
24w09a - 24w13a Written Books updated to these versions will become blank once updated to 24w14a or later MC-270325 Item Damage
24w09a - 24w14a All overstacked items will be converted to single item stack and attempting to save the game with overstacked items will cause a crash. MC-269680 Item Damage
1.20.5 The two lower items in trader llama chests are destroyed upon upgrading into 1.20.5 from previous versions. MC-271109 Item Damage

1.21

Version Issue Source Danger
24w18a - 24w19b Generating new chunks can cause the game to hang indefinitely. The game must either be closed manually or killed by the server watchdog. MC-271854 Crash
24w19a Crash when killing a villager. MC-271843 Crash
24w20a Crash when an entity dies while inflicted with oozing effect. MC-272043 Crash
1.21 Pre-Release 1 End crystals in fire will explode. End crystals atop end pillars instantly explode when player enters the End dimension. MC-272550 Entity Damage
24w34a Crash when trying to open GUIs with Fabulous graphics. MC-275566 Crash
Crash when pressing F3 + A to reload chunks. MC-275323 Crash
24w36a Crash when a boat is destroyed by a hazard. MC-276476 Crash
Crash when pick blocking a boat in creative mode. MC-276383 Crash
When 3 or more skeletons shoot their bows at once the game crashes. MC-276383 Crash
24w37a Viewing the player inside the inventory whilst effected by glowing and invisibility crashes the game. MC-276621 Crash
24w40a Any furnace that has entries in the RecipesUsed tag will lose its block entity upon reloading, deleting any items inside and all stored recipes. MC-277144 Block Damage
24w44a Selecting the void preset in the superflat customize menu crashes the game. MC-277929 Crash
Opening a loom crashes the game. MC-277955 Crash
Certain explosions[test] near a creaking whilst it's in its death animation can crash the game. MC-277967 Crash
1.21.2 Pre-Release 3 Chunks randomly destroy all block entities inside them on unload / reload (more information needed). MC-277548 Block Damage
25w09a Crash when rendering a breeze. A hardlock if the breeze cannot be unloaded by decreasing view distance. MC-280322 Hardlock
Crash when rendering a warden. A hardlock if the warden cannot be unloaded by decreasing view distance. MC-280303 Hardlock
25w09a - 25w09b Crash when rendering a slime on some systems using Intel graphics. A hardlock if the slime cannot be unloaded by decreasing view distance. MC-280337 Hardlock
25w15a - 1.21.7 Release Candidate 1 Crash when bogged, skeleton, stray, wither skeleton or vindicator ride a turtle. MC-299126 Crash
25w16a Crash after startup on some systems using AMD graphics. MC-296750 Crash
1.21.6 - 1.21.7 Release Candidate 1 Crash upon startup on some systems using AMD graphics. MC-298879 Crash
25w31a Crash upon interacting with a group of more than 3 connected shelves. MC-300121 Crash
25w34b Crash when trying to render a glowing enchanted item (e.g. zombie holding enchanted sword inflicted with the Glowing status effect). A hardlock if the glowing entity cannot be unloaded by decreasing view distance. MC-301290 Hardlock
25w36a Crash when loading an ender chest. A hardlock if ender chest cannot be unloaded by decreasing view distance. MC-301745 Hardlock
25w41a World fails to load with “Invalid player data” error message when the player has an active effect. A hardlock until active_effects is deleted from level.dat. MC-302672 Hardlock
25w42a Piglins, piglin brutes and hoglins zombify in the Nether. MC-303138 Entity Damage
25w44a World creation does not create stats folder, which means all stats are lost when exiting world. Manually creating stats folder inside world folder will allow stats to save. MC-303704 World Files
1.21.11 Pre-Release 1 Crash when loading game without an existing options.txt file. MC-304369 Crash

MinecraftEdu

Version Issue Source Danger
MinecraftEdu 1.7.10 Build 22 Attempting to ride minecart crashes the game. N/A Crash
Throwing an enderpearl hardlock the game. N/A Hardlock
MinecraftEdu 1.8.9 Build 3 Loading a naturally spawned minecart with chest from a mineshaft hardlocks the game. N/A Hardlock

4k

Version Issue Source Danger
4k-021742 ID 255 blocks are produced by the generator occasionally, while these are valid in this version, they are not in the next (4k-040144), and must be stripped with a converter before updating N/A Chunk Corruption

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 MC-31222. bugs.mojang.com.
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