CurseForge · Minecraft mod
DEUF - Duplicate Entity UUID Fix
Changes UUIDs of loaded Entities in case their UUIDs are already assigned (and removes log spam).
Quick answer
Which DEUF - Duplicate Entity UUID Fix release should I use?
DEUF - Duplicate Entity UUID Fix deuf-1.21.1-1.3.jar targets 1.21.1 with NeoForge. The project page does not say whether this file belongs on the client, dedicated server, or both. No extra mods listed for this file.
Where it goes
Is DEUF - Duplicate Entity UUID Fix required on the client, server, or both?
The project page does not say whether this file belongs on the client, dedicated server, or both.
The source does not explicitly classify this release as client-only or server-only.
What else does DEUF - Duplicate Entity UUID Fix deuf-1.21.1-1.3.jar need?
deuf-1.21.1-1.3.jar. Change the file and its required mods may change too.
This file does not list any required mods. Do not add a library just because a different file uses it.
This file does not list any required or optional mods.
Before you install it
Add DEUF - Duplicate Entity UUID Fix without breaking your instance.
Built for DEUF - Duplicate Entity UUID Fix deuf-1.21.1-1.3.jar. Pick another file and the loader, install side or required mods may change.
- 01
Stick to this file
Use deuf-1.21.1-1.3.jar. It targets 1.21.1 with NeoForge; another release may have different loader, side or dependency requirements.
- 02
Bring the mods it needs
This file does not list any required mods. Do not add a library just because a different file uses it.
- 03
Put it on the correct side
The project page does not say whether this file belongs on the client, dedicated server, or both.
- 04
Pick the file you checked
Use the “Get this file” button beside deuf-1.21.1-1.3.jar. It opens that exact file at the source.
About this project
What does DEUF - Duplicate Entity UUID Fix add?
"Keeping entity minecraft:xxxx that already exists with UUID xxxx"
Now that message can occure 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 occure anymore for that exact entity, which now has a non-duplicate UUID.
I have not tested it a lot. But all short tests I have done were positive and bug free. Still: BACK UP YOUR WORLD BEFORE USING.
Example:
Without Mod:
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID bd4f648f-ca0d-4680-9ed5-d28c68356379 [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 1bfcaf96-e93d-4dd8-a402-dc000794acae [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 2a01ea3a-1ac2-48fa-9731-1399c3f5d256 [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID c77765cb-f3fa-42d8-9326-52fa7e176dad [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID bd4f648f-ca0d-4680-9ed5-d28c68356379 [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 1bfcaf96-e93d-4dd8-a402-dc000794acae [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 2a01ea3a-1ac2-48fa-9731-1399c3f5d256 [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID c77765cb-f3fa-42d8-9326-52fa7e176dad [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID bd4f648f-ca0d-4680-9ed5-d28c68356379 [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 1bfcaf96-e93d-4dd8-a402-dc000794acae [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 2a01ea3a-1ac2-48fa-9731-1399c3f5d256 [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID c77765cb-f3fa-42d8-9326-52fa7e176dad [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID bd4f648f-ca0d-4680-9ed5-d28c68356379 [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 1bfcaf96-e93d-4dd8-a402-dc000794acae [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 2a01ea3a-1ac2-48fa-9731-1399c3f5d256 [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID c77765cb-f3fa-42d8-9326-52fa7e176dad [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID bd4f648f-ca0d-4680-9ed5-d28c68356379 [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 1bfcaf96-e93d-4dd8-a402-dc000794acae [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 2a01ea3a-1ac2-48fa-9731-1399c3f5d256 [17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID c77765cb-f3fa-42d8-9326-52fa7e176dad
With Mod (first load):
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID bd4f648f-ca0d-4680-9ed5-d28c68356379
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 1bfcaf96-e93d-4dd8-a402-dc000794acae
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 2a01ea3a-1ac2-48fa-9731-1399c3f5d256
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID c77765cb-f3fa-42d8-9326-52fa7e176dad
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID bd4f648f-ca0d-4680-9ed5-d28c68356379
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 1bfcaf96-e93d-4dd8-a402-dc000794acae
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 2a01ea3a-1ac2-48fa-9731-1399c3f5d256
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID c77765cb-f3fa-42d8-9326-52fa7e176dad
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID bd4f648f-ca0d-4680-9ed5-d28c68356379
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 1bfcaf96-e93d-4dd8-a402-dc000794acae
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 2a01ea3a-1ac2-48fa-9731-1399c3f5d256
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID c77765cb-f3fa-42d8-9326-52fa7e176dad
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID bd4f648f-ca0d-4680-9ed5-d28c68356379
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 1bfcaf96-e93d-4dd8-a402-dc000794acae
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 2a01ea3a-1ac2-48fa-9731-1399c3f5d256
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID c77765cb-f3fa-42d8-9326-52fa7e176dad
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID bd4f648f-ca0d-4680-9ed5-d28c68356379
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 1bfcaf96-e93d-4dd8-a402-dc000794acae
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID 2a01ea3a-1ac2-48fa-9731-1399c3f5d256
[17:41:21] [Server thread/WARN] [net.minecraft.world.WorldServer]: Keeping entity minecraft:painting that already exists with UUID c77765cb-f3fa-42d8-9326-52fa7e176dad
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from bd4f648f-ca0d-4680-9ed5-d28c68356379 to ae673ae3-2d57-4cf0-b192-87e4dee826d5
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from 1bfcaf96-e93d-4dd8-a402-dc000794acae to b727c571-7fd0-4e98-8bf2-fd63c935dbc5
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from 2a01ea3a-1ac2-48fa-9731-1399c3f5d256 to 6a6019d7-7c7f-4e90-8c38-9b7de5799efe
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from c77765cb-f3fa-42d8-9326-52fa7e176dad to dd1dc13a-7014-43a2-8dcd-9a242319db28
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from bd4f648f-ca0d-4680-9ed5-d28c68356379 to 1cd933f4-0fe9-4adc-ba88-49e45362922f
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from 1bfcaf96-e93d-4dd8-a402-dc000794acae to 1d2939bd-aa00-488d-9f51-64da4d684b43
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from 2a01ea3a-1ac2-48fa-9731-1399c3f5d256 to 4fa92741-e4de-4878-8de5-3b04ed68aef2
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from c77765cb-f3fa-42d8-9326-52fa7e176dad to 19595751-d5b1-416e-b885-11c0ada925ff
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from bd4f648f-ca0d-4680-9ed5-d28c68356379 to e7fa7ce7-55b4-411f-b6c9-8740dae0d812
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from 1bfcaf96-e93d-4dd8-a402-dc000794acae to 5240568b-3d40-4837-8ca5-cd3b48519d8a
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from 2a01ea3a-1ac2-48fa-9731-1399c3f5d256 to f28fb4ba-b509-40ad-9a97-b9cee67406e1
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from c77765cb-f3fa-42d8-9326-52fa7e176dad to 42999a16-8e11-42ed-b83e-bc3cdee031b8
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from bd4f648f-ca0d-4680-9ed5-d28c68356379 to 0aa6193b-0662-4c11-be18-22031040fb37
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from 1bfcaf96-e93d-4dd8-a402-dc000794acae to d40910d1-213f-4e10-8a54-25c0694b4124
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from 2a01ea3a-1ac2-48fa-9731-1399c3f5d256 to 85099341-acc6-44eb-a8b0-af86ca08446b
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from c77765cb-f3fa-42d8-9326-52fa7e176dad to a4ed61fa-098d-4fab-be2c-d1eee9c06b62
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from bd4f648f-ca0d-4680-9ed5-d28c68356379 to 6bd662c4-6555-438d-a202-a6b962cd56a1
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from 1bfcaf96-e93d-4dd8-a402-dc000794acae to 04a9acdd-6bb4-4c28-9ad7-39fdbc395bad
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from 2a01ea3a-1ac2-48fa-9731-1399c3f5d256 to ed93b32a-58f1-436e-80ac-012e52cedf81
[17:41:21] [Server thread/INFO] [uuidfix]: Changing UUID of entity minecraft:painting that already existed from c77765cb-f3fa-42d8-9326-52fa7e176dad to e13f6b2d-637d-448e-b371-f10e77be5aff
With Mod (second load and beyond):
Project description from CurseForge.
Pick your setup
DEUF - Duplicate Entity UUID Fix by Minecraft version and loader
Choose the version and loader you play, then open the matching release.
1.20.2
2 loader builds1.20.1
1 loader build1.19.4
1 loader build1.19.3
1 loader build1.19.2
1 loader build1.19.1
1 loader build1.19
1 loader build1.18.2
1 loader build1.16.5
1 loader build1.16.4
1 loader build1.16.3
1 loader buildShowing the newest 12 of 19 game versions. Older files are in the list below.
Check the dependencies, then try the file in a copied instance before changing a world you care about.
Recent files
DEUF - Duplicate Entity UUID Fix versions and loaders
deuf-1.21.1-1.3.jar
4 Jun 2026
deuf-forge-1.20.2-1.3.jar
15 Nov 2023
deuf-1.20.2-1.3.jar
15 Nov 2023
deuf-1.20.1-1.3.jar
20 Jun 2023
deuf-1.19.4-1.3.jar
28 Apr 2023
deuf-1.19.3-1.3.jar
1 Mar 2023
deuf-1.19.2-1.3.jar
10 Aug 2022
deuf-1.19.1-1.3.jar
28 Jul 2022
deuf-1.18.2-1.3.jar
23 Jul 2022
deuf-1.19-1.3.jar
23 Jul 2022
deuf-1.19-1.2.jar
20 Jul 2022
deuf-1.18.2-1.2.jar
20 Jul 2022
Looking for an older file? The official CurseForge project page is in Resources.

