Ever since I upgraded, I've been running into a problem. When I've tried to add or change artwork for a video (a movie, haven't tried anything else), often iTunes will freeze. Then, when I force quit and reopen it, all the artwork has disappeared, leaving only a white, horizontal box. When I try to play the video, it's gone, it only plays black for however long the movie is (no audio either). So I delete from iTunes and then put the file back in -- no change, still black. It seems to have messed with the file somehow. I was able to restore both movies that this happened on, but it's happened twice now and is really frustrating. Any ideas on what the problem is?