No problem, I appreciate your efforts.
1.) Use / start either the UE 4.4 version downloaded via the Launcher or built from source - doesn’t matter.
2.) Create a new project, the simplest one is sufficient (e.g. “Blank”, “A clean empty project…”)
3.) Create a new material and open it in the material editor.
4.) Add whatever node; the simplest node like a scalar constant is sufficient.
5.) Make sure the “realtime rendering” icon in the material editor viewport is selected (the stop watch / clock symbol at the top right side of the viewport has to be orange / selected).
6.) Make sure the node you created is selected. Do a Ctrl-C / Ctrl-V => Crash !
7.) Repeat Steps 1.) to 4.) Then make sure that the realtime rendering icon (described in 5. above) is not selected / gray.
8.) Repeat Point 6.) as described above => No Crash ! You can enable realtime rendering again after Ctrl-V.
It seems that the problem is related to the realtime rendering preview window in the material editor.
The Exception is thrown near the line “if (bUniformExpressionSetMismatch)” in file ShaderBaseClasses.cpp of the Unreal Engine source code.:
TBasePassVSFNoLightMapPolicy shader uniform expression set mismatch for material PreviewMaterial_0/WorldGridMaterial.
Shader compilation info: WorldGridMaterial
Material render proxy compilation info: Compiling WorldGridMaterial: Platform=PCD3D_SM5, Usage=MSM_DefaultLit, BLEND_Opaque, SpecialEngine, TSNormal
Shader uniform expression set: 1 vectors, 1 scalars, 2 2D textures, 0 cube textures, shader map 000000000E295D00
Material uniform expression set: 1 vectors, 1 scalars, 2 2D textures, 0 cube textures, shader map 000000000E121F80
Btw.: I am using an AMD Radeon HD7950 card (newest Catalyst productive drivers V 14.4), Win7-64 SP1 Ultimate, 16GB RAM, Intel 6-core proc.