Here is a power tip from Matt Vanacoro in this YouTube video:
If you find that things are running really slow or buggy and crashing, one of the most common things I’ll do and I’ve done this for people on the road is to create a new user on your Mac.
Making a fresh user comes along with fresh permissions can sometimes take out problems you didn’t even know that are there and that can be a band aid.
Nine times out of ten, when people make a new, fresh user a gig file that originally crashed works.
In that case obviously, something with your permissions is screwed up.
(watch the linked video to learn more)