When I add personal/research notes to certain people FTM crashes.
It only seems to happen with certain people, i.e. I can add notes to dozens of people, but so far I've found two people for whom FTM just doesn't seem to want any updated notes. All I have to do to make it crash is to open the notes of one of those people, type one letter, press ok, and bam - everything goes white and I get a message saying the program is no longer responding.
Incidentally, the two people (so far) that crash FTM are a father and daughter. There are other siblings for whom I can edit their notes without problems.
When FTM reloads it says it closed improperly and I might need to compact the file. I've tried that, and it reduced the size by a little bit, but didn't fix the problem.
EDIT: It turns out another of the siblings' notes can't be edited either. So I'm up to three now.