I just wanted to put a warning out there. If you're using Time Machine, make sure you exclude your Aperture Library from your backup list... Here's why. Your backup disk will get full very, very fast. Every time you make a change to your Aperture photos, Time Machine will re-backup your ENTIRE photo library because Time Machine looks at your whole Library as if it is one giant file. So to avoid this, you must exclude Aperture and make sure you use the Vault feature from within Aperture.