I know that the appearance wizard can cause crashes and for a while I had that problem but now it works just fine. No idea why as nothing’s changed with my system that I can think of. However…
I just noticed that when you start the wizard it wipes out all placeables and environment objects and then puts them back when you exit it. It also turns on and off light spheres which is really annoying because then I have to turn them off again so I can see what I’m doing.
So maybe that’s some sort of insight into why it can be temperamental, I don’t know, but if it helps anybody to work out why it misbehaves and they can get theirs working by wiping out visible stuff then that’s all good.