[Fixed] Editor crashes 100% when trying to build the game

Hello,

We're investigating an upgrade from 2019 LTS to 2020.2 in our project and even though the Editor improvements are cool, we unfortunately haven't been able to build the project on 2020.2b11.

We have a 100% crash when trying to build the asset bundles through our editor tools with a stacktrace as follow:

Code (CSharp):

1. Stack Trace of Crashed Thread 54496:
2. 0x00007FF7755D78DA (Unity) winutils::CrashHandler::DefaultSignalHandler
3. 0x00007FF775416657 (Unity) HandleSignal
4. 0x00007FF77893A17A (Unity) seh_filter_exe
5. 0x00007FF778CF5329 (Unity) `__scrt_common_main_seh'::`1'::filt$0
6. 0x00007FF778907E48 (Unity) _C_specific_handler
7. 0x00007FFC3BEE121F (ntdll) _chkstk
8. 0x00007FFC3BEAA259 (ntdll) RtlRaiseException
9. 0x00007FFC3BEDFE8E (ntdll) KiUserExceptionDispatcher
10. 0x00007FF777B3E580 (Unity) Mesh::Transfer<StreamedBinaryWrite>
11. 0x00007FF775549AB3 (Unity) SerializedFile::WriteObject
12. 0x00007FF775511C13 (Unity) PersistentManager::WriteFile
13. 0x00007FF775513629 (Unity) PersistentManager::WriteFile
14. 0x00007FF7763002A4 (Unity) WriteSharedAssetFile
15. 0x00007FF7762DBC8B (Unity) CompileSharedAssetsFile
16. 0x00007FF777E8AD61 (Unity) BuildSharedAssetsFile
17. 0x00007FF777E8626F (Unity) BuildPlayerData
18. 0x00007FF777E8E951 (Unity) DoBuildPlayer_Build
19. 0x00007FF777E8D5B7 (Unity) DoBuildPlayer
20. 0x00007FF776287CC4 (Unity) BuildStreamedSceneBundle
21. 0x00007FF776285591 (Unity) BuildAssetBundlesInternal
22. 0x00007FF77628320F (Unity) BuildAssetBundles
23. 0x00007FF77735EF51 (Unity) BuildPipeline::BuildAssetBundlesWithInfoInternal
24. 0x00007FF7771F88BF (Unity) BuildPipeline_CUSTOM_BuildAssetBundlesWithInfoInternal
25. 0x0000023150F8F2D7 (UnityEditor.CoreModule) UnityEditor.BuildPipeline.BuildAssetBundlesWithInfoInternal()
26. 0x0000023150F8EF8B (UnityEditor.CoreModule) UnityEditor.BuildPipeline.BuildAssetBundles()
27. 0x0000023150F8EE93 (UnityEditor.CoreModule) UnityEditor.BuildPipeline.BuildAssetBundles()

I have also reported the crash in fogbugz case #1292739 with more information there.
Is this a known issue or is there a workaround to that crash as of now?
I should note, since this crash is related to writing files, that our project is also on Perforce (I tried setting the project to work offline but nothing changed).

Thanks,
Christopher.

 

More information:
It's not just the asset bundles, we've got the same crash if we're just trying to build the project with no asset bundles.

Edit: We managed to find a workaround with the spotlight team, and a confirmation that the issue is fixed in b12, here's the workaround for anyone wondering:
In ProjectSettings.asset, change "VertexChannelCompressionMask: -1" to "VertexChannelCompressionMask: 0"