Does that happen to only one file or generally?
Try to open a cmp file without it’s .sur that might help find the bug because .surs usually cause hardcmp crashes.
If I move cmp to folder on its own all I see is white, but no crash
probably the .sur then, you have to move the mat file into the folder as well for the textures to show - either that or point HardCMP at the mat file, do that by going to file/open mat