UE5 crashing when I open Character BP

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

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