Whenever I insert an audio CD into my iMac, it mounts, then when I launch iTunes, the program accesses CDDB Gracenote, then for a split second the correct songs appear, then the whole thing disappears. iTunes reverts to the main music screen, the CD no longer appears in the left sidebar and it even disappears from the Finder. I have to use Disk Utility to eject the disc. I've tried this with a number of different audio CDs. I'm running Leopard and iTunes 7.5. Any ideas?