A while ago I moved my iTunes library to an external drive. I followed the instructions (keep music organised, consolidate library etc) and all was fine. I started to import my music collection and today I noticed that some of the music and films have been stored on the HDD of my iMac instead of the external drive. I'm assuming I can "consolidate library" to fix it, but what's to stop it happening again? Part of the reason for doing this was to make sure everything is being stored in the one place for backup purposes. Any ideas? Thanks!