Im trying to upgrade to leopard. I just bought a 320GB hard drive to replace the 80GB hard drive in my Macbook Pro. I installed the new hard drive into an external firewire case and formatted it. I formatted the volume with Mac OS Extended (Journaled). I used SuperDuper! to clone my old hard drive on to the new hard drive. Everything works fine. Now I want to upgrade the new hard drive to Leopard before I install it into my Macbook. I started the Leopard install and the new hard drive has a red Exclamation mark so I cant install Leopard on it. Here is the error it gives. You cannot install Mac OSX on this volume. To enable installation on this volume open Disk Utility from the Utilities menu and repartition the disk as GUID Partition Table. Note: you will lose all data on this disk by repartitioning it. My old hard drive is formatted the same way and I can install Leopard on it. Do you think that it has a problem installing on the Firewire drive? Do you think if I install the new drive into my Macbook the way it is I wont have to reformat the drive or should I just reformat it not and get it over with?