Java Edition:World Save Insertion

World Save Insertion Example.png

World Save Insertion
The terrain of a superflat world after using level.dat regeneration twice. Once changing settings to make the world amplified, and another to change it to a buffet world with floating islands and the badlands biome.
Type	level.dat
Versions Obtainable
Version range	Infdev 20100327 - 24w20a (present)

Warning: Game Crash 

This feature can crash the game. Perform at your own risk.

Warning: Corruption 

This feature can corrupt your world. Perform at your own risk.

Warning: Requires External Editing 

This method requires external editing which can corrupt your world. Perform at your own risk.

World Save Insertion is the process of forcing the game to load or generate a world, despite either being incompatible with the current version or containing already existing files, respectively. These methods rely on flawed checks within the world loading and creation processes.

Warning

Depending on the version, this feature may be dangerous and result in crashes or corruption. In order to avoid any potential issues, it is highly recommended make at least one world backup before attempting this feature. If performing level.dat regeneration, one should also load their world normally at least once in the version they are performing the regeneration in to ensure all files that need to be converted are, if possible.

Force Load

Many versions of the game have locks placed on certain versions, such as April Fools' snapshots or worlds with experimental toggles enabled. Obviously, this can be annoying when one wishes to update their world into or out of these versions for the purposes of obtaining discontinued features. However, there is an easy way around this restriction.

Instructions

1. Make at least one world backup!
2. Make sure Minecraft is closed so it does not hold a session lock on your world.
3. Open your .minecraft folder, and navigate to your world in the saves folder.
4. Rename your world folder to something else (e.g. add a 1 after the name), or move your world folder to another location outside of the saves folder.
5. Open Minecraft, and open the world generation screen.
6. Inside the "World Name" field, type out the exact name of your world (case sensitive!). Make sure this does NOT include your added character, if you added one.
   • Example: if your world is named "New World", fill in the name as "New World".
7. Generate the dummy world, and then return to the world selection screen. The world's settings don't matter.
8. Either delete or rename the world you just generated (do this outside of the game!). Make sure you are still on the world selection screen and see the dummy world.
9. Either move your world back to the saves folder, or undo the name change, which ever you performed.
10. Join the dummy world slot on the world selection screen.
11. Congrats, you've just tricked the game into loading an incompatible world!

Level.dat Regeneration

Some features documented on this wiki may require level.dat regeneration to obtain, such as if one desires to generate the Beta 1.6 Test Build 3 Debug Chests in an already existing world. These methods will trick the game into thinking that your world doesn't exist so you can create a "new" world. This is also useful if one desires to change various settings with their world, such as enabling experimental toggles. For a full list of available world settings, see the uses section.

Preparations

Before attempting this feature, it is important to disclose that it may require deleting or moving your level.dat file. If you are in any version before 12w18a (1.3 snapshot), this will also result in deleting your player data, including your experience, inventory, game mode, spawn point, status effects, and all other potentially discontinued data. If you are in 12w18 or any version after, your player data will be preserved via the players or playerdata folder, which will store your player data separately from the level.dat file.

External Editing Method

The world creation screen in 23w05a (1.19.4 snapshot) and above

Instructions

1. Make at least one world backup!
2. Make sure Minecraft is closed so it does not hold a session lock on the world.
3. Open your .minecraft folder, and navigate to your world in the saves folder.
4. Delete or move the following files from within your world folder: level.dat and level.dat_old.
   • Moving is suggested if you want to keep any discontinued data contained in these files.
5. If you are in 19w12a (1.14 snapshot) or later, you need to either rename your world folder to something else (e.g. add a 1 after the name), or move your world folder to another location outside of the saves folder.
6. Open Minecraft, and open the world generation screen.
7. Inside the "World Name" field, type out the exact name of the world (case sensitive!) you are trying to force a new level.dat to generate in. Make sure this does NOT include your added character, if you added one.
   • Example: if your world is named "New World", fill in the name as "New World".
8. Set the world seed and settings how you want them, and return to a screen with the "Create New World" button.
9. If you are in 19w12a (1.14 snapshot) or later, move your world back to the saves folder, or undo the name change, which ever you performed.
10. Click "Create New World".
11. Congrats, you've regenerated your level.dat file!

Ingame Method

This section is a work in progress. 

Please help in the creation of this article/section by expanding or improving it.

This method is still being tested. Currently, it is the easiest and the first reliable way to do WSI fully in-game. This has been tested on 1.12.2 and possibly works in all versions with some minor tweaks.

Instructions

1. Make at least one world backup!
2. Launch two Minecraft instances and open on both the "Singleplayer" screen.
3. Open the world on the first instance.
4. Delete the world on the second instance (but do not close the first instance).
5. Create a new world with the same file name on the second instance.
6. Close the first Minecraft instance.
7. Save and quit the second instance.

Additional Notes

• If the seed is not specified, a new seed will be randomly chosen.
• The world spawn will most likely be different, and you may spawn in unfamiliar terrain in versions before 12w18a (1.3 snapshot).
• If you experience any difficulties, refer to the "Help" section of this page.

Level.dat Regeneration Uses

This section covers a list of what can be done with level.dat regeneration. These include, but are not limited to:

1. Changing the world's gamemode
2. Changing the world's difficulty (even if locked)
3. Enabling or disabling cheats
4. Changing the world type (default, superflat, large biomes, amplified, single biome, etc.)
5. Changing the world's seed
6. Enabling or disabling structure generationn
7. Generating a bonus chest
8. Changing the world's game rules (20w17a (1.16 snapshot) and above)
9. Enabling or disabling data packs or experimental features
10. Force the loading of "incompatible" versions, e.g. 22w13oBAAT or 23w13a_or_b
11. Forcing the generation of the Beta 1.6 Test Build 3 Debug Chests in an old world
12. Spawn another 12,000 XP Ender Dragon and dragon egg in 15w31a (a 1.9 snapshot) and above. You have to additionally have to break all end portal blocks within a 17x17 chunk area centered on the 0,0 chunk in the end before regenerating level.dat to achieve this. In 16w40a (a 1.11 snapshot) and above, one will also have to break all end gateway blocks. Due to a bug, the level.dat file doesn't actually have to be regenerated if performing this before 21w19a (a 1.17 snapshot), but if one does not use level.dat regeneration, the gateways will not regenerate.

Help

If you have any problems please refer to the Help page.