Hi, so I've been playing a custom modded minecraft world for a pretty long time. I've just run into a problem: it says that the backup level.dat is being used, since all block ids are used up in the world I've been playing in. I removed several large mods, so here's basically my problem: is there a way to remove unused block/item ids from a world? I know even if you remove a mod the block/item ids for it are still saved to the world and using up space.

I can't update or add any mods to my current world unless I find a fix to this problem. I've spent a ton of time on this world and I really don't want to restart or have to never my mods...

If you can/try to help I thank you a bajillion times in advance it means the world to me.

You'd have to edit level.dat with a nbt editor.

Not sure how you guys are churning through bids sofat but you can always manually delete the ones you dont care about in the level.dat.

We take no responsibility for you world if you do this.

Thanks for the response- could I remove the ids using NBTExplorer? I've started it up a few times but I don't know where block ids are saved in the level.dat folder.

Anyone have experience with this tool or can recommend another one?

After reading a few more threads and doing research, I think I know what I need to do now- if I manually remove the ids then new mods will replace those blocks. I guess what I can do is force delete the ids, copy + paste my base into a new world using the same seed with the current mods, then I'll have free ids and shouldn't have issues provided none of the blocks from my old mods are near my base.

In theory I'll be able to update/add mods again... I'll try in a little while and post what my progress is.

Do I need to delete the 'BlockedItemIDs' file in level.dat to free up the block/item ids? I can't find anywhere else they could be located...