4.12p3 will crash continously with the shader files when compiling defaultgridmaterial if you dont run a regular template project and compile materials before opening preview
Edit: still crashing, verified engine to replace shaders to default, ran a first person template and made sure the material in question was compiled, saved/closed, ran fresh project and
shadercomilerworker.exe loads up the cpu like youd expect and project gets to 45% thenc rashes.
Preview versions for a reason.
Fatal error: [File:D:\Build\++UE4+Release-4.12+Compile\Sync\Engine\Source\Runtime\Engine\Private\ShaderCompiler\ShaderCompiler.cpp] [Line: 1559]
Failed to compile default material /Engine/EngineMaterials/WorldGridMaterial.WorldGridMaterial!