Cloth Tools gets stucks on Applying Cloth./Apex/NV

Hey, i have an strange Problem, when i TRY to Apply an Cloth on my Mesh / 40 k Vert, not matter if Apex/OR Editor itself, the Editor Freezes, and than i get an Crash

Assertion Failed: Size <= BucketSizes[Lower]"/Ue4 Path / GPuSkinVertexFactory.cpp [Line:92]

anyone know what i need to do?

Hope someone can help me

Thanks!