"Errors in currently selected datapacks prevented the world from loading." when updating world from 1.16.5 to 1.18.2

[Starvixen64]

Recently updated from 1.16.5 to 1.18.2 as I found that all my mods had updated to newer versions, so I could upgrade them without needing to drop any.

Weirdly, worlds created in 1.18.2 work fine and splendidly with all mods I'm using, but playing my main world (1.16.5, possibly gen'd in 1.14 but I think 1.16.5) in 1.18.2 just leads to this message.

Errors in currently selected datapacks prevented the world from loading. You can either try to load it with only the vanilla data pack ("safe mode") or go back to the title screen to manually fix it

What would be causing this?

Modlist : https://i.imgur.com/AcKjimg.png (using Forge 1.18.2-40.1.73)

debug.log : https://www.textbin.xyz/?51a78db1807352d8#CTwkbgkon74hQCBZ324s4PB8N4dYWXb2fPeVqNKbPH8C

Edited August 18, 2022 by Starvixen64
hyperlinks

[warjort]

[18Aug2022 01:12:41.158] [Render thread/ERROR] [net.minecraft.world.level.storage.LevelStorageSource/]: Exception reading C:\Users\Princess\AppData\Roaming\.minecraft\saves\16_5 Creative (Azimuth) NonBOP-copy\level.dat
java.lang.IllegalStateException: Unable load old custom worlds.
	at net.minecraft.util.datafix.fixes.WorldGenSettingsDisallowOldCustomWorldsFix.m_185165_(WorldGenSettingsDisallowOldCustomWorldsFix.java:25) ~[client-1.18.2-20220404.173914-srg.jar%2374!/:?]

Your world uses the old custom world format that minecraft no longer supports in 1.18

[Starvixen64]

9 hours ago, warjort said:

[18Aug2022 01:12:41.158] [Render thread/ERROR] [net.minecraft.world.level.storage.LevelStorageSource/]: Exception reading C:\Users\Princess\AppData\Roaming\.minecraft\saves\16_5 Creative (Azimuth) NonBOP-copy\level.dat
java.lang.IllegalStateException: Unable load old custom worlds.
	at net.minecraft.util.datafix.fixes.WorldGenSettingsDisallowOldCustomWorldsFix.m_185165_(WorldGenSettingsDisallowOldCustomWorldsFix.java:25) ~[client-1.18.2-20220404.173914-srg.jar%2374!/:?]

Your world uses the old custom world format that minecraft no longer supports in 1.18

That's weird, this wasn't a custom world. I did once (I think) edit it between vanilla and Biomes o Plenty type worlds, but all that block data would've been gone anyway. Is there some way to update the world to work with 1.18?

[warjort]

Mojang didn't provide a way to do that. Presumably because it is a lot of work to do it.

 

This reddit thread discusses how to do it manually by editing the json, but it requires a lot of technical knowledge on the old custom world format and the new world format:

https://www.reddit.com/r/minecraft_configs/comments/hz4ti7/is_it_technically_possible_to_convert_an_old/

But this has a number of problems, e.g.

* Since that thread is 2 years old, the information on that thread will be out-of-date. 1.18 had major changes to world gen storage, hence your problem.

* It assumes a vanilla world, while you said you had Biomes o Plenty which will have additional world gen config that would needs to be converted

 

BTW: I think even in 1.16 the old custom world format wasn't really properly supported.

Instead it just kept any world chunks that you had already created and generated normal (non-custom) chunks for new ones?

Edited August 18, 2022 by warjort

[Luis_ST]

45 minutes ago, warjort said:

Mojang didn't provide a way to do that. Presumably because it is a lot of work to do it.

If i remember correctly vanilla World can be updated without problems, only modded Worlds will get corrupted.

[warjort]

7 minutes ago, Luis_ST said:

If i remember correctly vanilla World can be updated without problems, only modded Worlds will get corrupted.

No, this is the old buffet worlds or its precursor.

Mojang added a specific check to DFU (DataFixerUpper) that stops these worlds from being updated in the 1.18 snapshots.

[Starvixen64]

10 hours ago, warjort said:

No, this is the old buffet worlds or its precursor.

Mojang added a specific check to DFU (DataFixerUpper) that stops these worlds from being updated in the 1.18 snapshots.

Do you know of a way to check within NBT as to how the world was generated? Although I do remember possibly fiddling around with BOP at one point, I'm fairly positive this was never an old custom world; it was generated PAST when those became obsolete. Highly confused as to why this world is bugged out in this way

Edit: I've had a browse and the level.dat has a separate dimension from overworld, end, nether under "compactmachines:compact_world". I imagine this is because quite a long time ago I used the Compact Machines mod on this world; could this have something to do with it? I don't have practically any data left from that mod but it seems to linger in the NBT.

Edited August 18, 2022 by Starvixen64
eddity edit

[warjort]

The thing that DFU actually checks for is a "generator" without a "type".

https://minecraft.fandom.com/wiki/Custom#Generator_types

 

 

 

[Starvixen64]

All my dimensions read "minecraft:noise" for "type" under "generator". Is this not default worldgen behaviour?

[warjort]

Actually, I think I misread the code. This stuff can be quite difficult to read. 🙂

I think it is looking for a dimension without a type?

It is definitely looking for something within the world generation settings/dimensions that is missing a type.

Edited August 18, 2022 by warjort

[Starvixen64]

36 minutes ago, warjort said:

Actually, I think I misread the code. This stuff can be quite difficult to read. 🙂

I think it is looking for a dimension without a type?

It is definitely looking for something within the world generation settings/dimensions that is missing a type.

Fascinating - your suggestion and my hunch combined proved to be the solution!

I categorically knew that it was not a non-standard world type, so I had a browse through the NBT and just deleted out the compactmachines:compact_world tree data, as it's a remnant of a long-uninstalled (but very cool) mod, that left it's data in the NBT. Then I deleted everything from the "dimensions" folder in %appdata%/.minecraft/ without deleting the folder itself.

To my great relief, the world has succesfully loaded in 1.18.2, meaning I don't need to lose my most worked-on world to version incompatibility!

I'm not sure what the exact issue was, I just know it pertains to Compact Machines and something to do with how the 1.16.5->1.18.2 update treats it's dimensions. I imagine even after deleting the mod itself, it probably left the dimensions themselves (with machines inside) intact. To anyone encountering this/a similar issue, check if you have non-standard modded dimensions, especially those you don't use anymore. Seems to do the trick.

Thanks for the help! ❤️