Got my iTunes Library reading from an external USB drive. Nothing has changed in months. Though just recently, for 90% of my songs - iTunes can't locate them. I checked the directory where they've always been and they're still there. External drive is alive and kicking, connected to my Macbook. This sucks because I've got a gajillion playlists. And my iPhone and iPad will no longer sync these playlists. Suggestions/help?! I'd really hate to manually have to re-do all of my playlists again.