[BUG - Release] UE4SS Causes Player ID Change & Character Reset in Palworld Server

[Snoores]

Hello !

When installing UE4SS on my dedicated Palworld server, all existing player characters are lost, and I am forced to create a new character. After investigating, I found that when UE4SS is installed, my player ID changes when they connect, preventing the server from recognizing our character :

- If I remove UE4SS, my original character returns as expected.
- The issue persists across different UE4SS versions.
- My Players folder contains the correct character data, but UE4SS may prevents it from loading correctly.
- I noticed that two different save files are created for the same player :
    - Before installing UE4SS: Player ID is B79DC59E
    - After installing UE4SS: Player ID is 4DC6B307
    - This suggests that UE4SS may be altering how player IDs are assigned or recognized.

Steps to Reproduce

- Backup all server data from another Palworld server.
- Install a new dedicated Palworld server via SteamCMD.
- Restore the backed-up data (including Players folder).
- Start the server and connect—everything works fine (original character is present).
- Disconnect, install UE4SS, then restart the server.
- Reconnect to the server—the game forces me to create a new character.
- Remove UE4SS and restart the server.
- Reconnect—the original character is back.

Expected Behavior

- UE4SS should ideally not affect player identification.
- Installing UE4SS should allow existing players to keep their characters.

Additional Notes

- No additional mods are installed. I've even tried disabling built-in mods, but the issue persists.
- I suspect UE4SS may be altering save file encryption or how the game handles player IDs.
- Changing file permissions, manually restoring save data, and testing different UE4SS versions did not resolve the issue.
- The issue occurs when using backed-up data from another server and on the initial server.

Environment

- Game Version: 0.4.15.66880
- UE4SS Version: v3.0.1-39-g3320fc1, 3.0.1-333-gda0fa64, v3.0.1, v3.0.0, v2.5.2
- Server Type: Dedicated Server
- OS: Debian 11 (Wine) & Windows 11 (Hyper V VM)

Any insights or fixes would be greatly appreciated!

[UE4SS]

This seems suspiciously similar to #733, so this might be a regression.
I don't believe we narrowed down what the problem was, it just kind of went away when they updated to a newer version of UE4SS.

UE4SS doesn't do any save file alterations, or ID changes or anything like that on its own.
It seems more likely that the game detects that something changed that caused some kind of incompatibility.

I don't have time to test this right now, so the only thing I can suggest is to confirm you've removed all mods from all mod locations:

• Palworld/Pal/Binaries/Win64/Mods
• Palworld/Pal/Binaries/Win64/ue4ss/Mods
• Palworld/Pal/Content/Paks/LogicMods

[narknon]

Are you launching the server the exact same way as prior to installing ue4ss?

[Snoores]

Thanks for your responses!

Yes, I checked, and all the mentioned folders were empty, but the issue still persisted. Regarding how I launch the server, the process is always the same: on Linux, I use a container, and on Windows, I start it through Palworld.exe.

I performed a fresh install of the Palworld server on a new machine and installed only UE4SS_v3.0.1-333-gda0fa64 (without trying any other version), which resolved the issue. It's possible that some leftover files from previous UE4SS installations was still present when I've tried to installed this version.

Thanks again for your support—I really appreciate the help!

[SonnyFly]

Where u finde the UE4SS_v3.0.1-333-gda0fa64
I only find 340!

[Snoores]

It's probably the same version, just with a few extra commits. Version 340 might just mean there have been some updates since 333, but the changes could be minor.

[UE4SS]

Where u finde the UE4SS_v3.0.1-333-gda0fa64 I only find 340!

I suspect you might be looking at the experimental-latest tag.
That tag only hosts the latest commit for convenience.
If you want a particular commit, see the regular experimental tag: https://github.com/UE4SS-RE/RE-UE4SS/releases/tag/experimental