You can see me cause the issue here:
For some reason trying to change a texture I got refered to Worldgridmaterial I noticed it later on, saved it, it took a long time, but then crashed. All I really did was change or add some texture jpegs to whatever I was editing and since then it can no longer start.
Instead I get this:
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000000
UnrealEditor_AnimGraph
UnrealEditor_AnimGraph
UnrealEditor_AnimGraph
UnrealEditor_Kismet
UnrealEditor_Kismet
UnrealEditor_Kismet
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_UnrealEd
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor_CoreUObject
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
kernel32
ntdll