to a Western Digital 320 GB Passport HD. I took it out of the enclosure and put it in my MacBook. Here is some advice for anyone who will be doing an HD swap. If you use Time Machine, make your backup and DO NOT use the "Restore from Time Machine Backup" option when you first boot Leopard after install. Make an account of a random name, UPDATE using Software Update, and then, and ONLY then, use Migration Assistant to restore. The Time Machine Backup does NOT include the software updates for the OS even if you did the backup after the updates were applied. I made the mistake and restored before doing Software Update on the new install and I had to reinstall leopard again. Make sure you do Software Update first, then go on to restore your Time Machine Backup. Also, on a side note, the WD 320 GB 5400 RPM is a screamer. It is really quick and obviously, very large. I've still got ~230 GB after putting ALL of my stuff on. I'm very satisfied with that.