For some reason, I am suddenly unable to apply any custom materials. The Material Display manager opens as it should, you can browse and select a custom P2M or JPEG as normal, orientate/resize it, but then when you tick OK, it thinks and thinks and thinks for eternity. I've tried lots of different files, at different levels (part/body/face etc) which have all worked fine before.
I initially thought it was a problem linked to a large assembly i've been working on, but its the same problem if a create an entirely new part, having restarted the computer.
I seem to be able to apply default materials fine.
Does anyone have any ideas? I've got deadlines looming and without being able to apply materials i'm stuck!