DEUF – Duplicate Entity UUID Fix [NeoForge]

“Keeping entity minecraft:xxxx that already exists with UUID xxxx”

Now that message can occur quite often in case you use an old world. And there is no fix for it currently even though the bug is listed in the bug tracker for some time now. The logs (and server console, in case you have one – like me) also get spammed quite a lot so I thought I would make a mod which fixes those duplicate UUIDs and thus removes the spam.

Simply drag and drop the file into your mods folder. Clients do not need to install the mod to join your server (in case you use it for a server – like I do).

When installed, simply explore your world. Initially the spam will be more than before, since there should be an additional message which tells you that the UUID has been changed. But when reloading the world or restarting the server, that will not occur anymore for that exact entity, which now has a non-duplicate UUID.

Port of CAS_ual_TY’s DEUF to NeoForge 1.21.1+ under the MIT license.