I'm getting really frustrated by this. I have a large movie library stored on an external HD (added to iTunes by holding down Option when dragging), and I am adding the artwork for them & changing their video type from 'Home Movie' to 'Movie'. Whenever I try to change the metadata, either individually or a few at once, iTunes freezes and I have to quit it with Cmd-Opt-Esc. I've experienced the same thing when adding artwork to locally stored music too. Does anybody know a solution to this problem?