UE5 crashing when I open Character BP

TheAncientGame.log (88.4 KB)

I have a project that used to be in UE 5 Preview but is now UE 5.0 and when I hit play, the game works fine, but when I try to open the character blueprint, the whole engine crashes. The log seems to indicate there are .dll files missing. Research on this topic seems to have led me nowhere. I tried copying the files over to a new project and the same results happen in the new project. Other projects have not given me this error yet. Any idea how I can salvage this project? Thank you for your time.

You could try deleting the DerivedDataCache folder, I see some shader messages which are likely to be resolved when you do. Other problems might disappear as well.

This part:

PixWinPlugin: PIX capture plugin failed to initialize! Check that the process is launched from PIX.

Along with the top info:

LogWindows: Failed to load 'aqProf.dll' (GetLastError=126)
LogWindows: File 'aqProf.dll' does not exist
LogProfilingDebugging: Loading WinPixEventRuntime.dll for PIX profiling (from ../../../Engine/Binaries/ThirdParty/Windows/WinPixEventRuntime/x64).
LogWindows: Failed to load 'VtuneApi.dll' (GetLastError=126)
LogWindows: File 'VtuneApi.dll' does not exist
LogWindows: Failed to load 'VtuneApi32e.dll' (GetLastError=126)
LogWindows: File 'VtuneApi32e.dll' does not exist

Points at some problem with WinPix. However, I have never heard of it…

Message at the bottom is the direct reason, it is an assert.

Assertion failed: TargetNumVerts >= LimitNumVerts [File:D:\build\++UE5\Sync\Engine\Source\Developer\MeshSimplifier\Private\MeshSimplify.cpp

Related post:

I tried deleting the DerivedDataCache folder and the project still crashed when opening the Character BP. Here is the new log:
TheAncientGame2.log (82.1 KB)

It looks like I can open a data Blueprint, however when I try to open the full Blueprint for any Character the whole Engine crashes.

I deleted that one folder with all those assets with shader errors and now I can open the characters without crashing. I did not use those assets for anything, so I don’t know why those two things were in any way related. Some things are still a bit fishy, so I’m going to keep this thread open until I’ve done some more exploring. I feel like another crash is right around the corner.

Does it still crash on this assert? If so, did the related post give you any useful info? In their situation this particular error seems an engine issue with the current version of UE5.

[2022.04.13-23.57.22:190][936]LogWindows: Error: Error reentered: Assertion failed: TargetNumVerts >= LimitNumVerts [File:D:\build\++UE5\Sync\Engine\Source\Developer\MeshSimplifier\Private\MeshSimplify.cpp] [Line: 849] 

No, I don’t have the assert issue anymore after deleting the files, and I forgot to look at the related post.

Now that I look at it, I see someone mentioned problem files. For me, the problem files were the Warning preceding the error, which all came from a folder containing assets I was not using anyway, mostly Missing cached shadermap messages. I deleted the entire folder and containing a whole lot of assets which I did not want, and the error no longer triggered. Really weird, since they should have not had anything to do with my Blueprints in any way whatsoever.