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Thank you for reporting a bug to Unity. Based on internal discussions we managed to pinpoint the root cause of this issue to a scene desynchronization happening during an AssetDB refresh, caused by a mismatch in Build Settings/scenes between Edit Mode and Play Mode (especially when running MPPM). A fix was rolled out in Unity 6000.3.0b7 and 6000.4.0a3 (and newer releases), and we were not able to reproduce the bug on our side. We will close this case for now. If the issue is still happening for you and you're able to share additional details such as different projects, steps, hardware/software configuration, or logs - please let us know, and we'll be happy to re-evaluate.
Thank you for reporting a bug to Unity. Based on internal discussions we managed to pinpoint the root cause of this issue to a scene desynchronization happening during an AssetDB refresh, caused by a mismatch in Build Settings/scenes between Edit Mode and Play Mode (especially when running MPPM). A fix was rolled out in Unity 6000.3.0b7 and 6000.4.0a3 (and newer releases), and we were not able to reproduce the bug on our side. We will close this case for now. If the issue is still happening for you and you're able to share additional details such as different projects, steps, hardware/software configuration, or logs - please let us know, and we'll be happy to re-evaluate.
Steps to reproduce:
1. Open the attached project: IN-118499
2. Build the Player (Edit > Build)
3. Launch two instances of the newly built Player
4. In both Players go to “Quick Play“ -> “Matchmake“
5. Press '`' button to see the console and observe it
Expected result: Two Players connect to each other
Actual result: Two Players try to connect, then the Host checks for GhostPrefab gets and error: “The ghost collection contains a ghost which does not have a valid prefab on the client! Ghost: '' ('ENTITY_NOT_FOUND').“ and closes the connection. This can be seen in the game console.
Reproducible with: 1.0.0-pre.2(6000.2.8f1), 2.2.6(6000.2.8f1, 6000.3.0b6, 6000.4.0a2)
Could not test in: 6000.0.59f1 (Multiplayer package was not implemented)
Reproducible on: Windows 11
Not reproducible on: No other environments tested
Note: If while launching 2 instances of the Player you get an error saying that only one instance can be launched go to Edit → Player Settings → Player → uncheck “Force Single Instance”.
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