I have a FreeAgent XTreme 1.5TB external HD (P/N 9ZE7A6-500). I realize that out of the box it will not be recognized by a Mac running OS X. However, the drive does not appear when I run the Mac Disk Utility. Thus, I cannot reformat the drive. This occurred with a PowerBook G4 running OS X 10.5.5 and a PowerBook G4 running OS X 10.4.11. This occurred when connecting to the drive by both Firewire 400 and by USB 2.0. The drive is okay, because my Windows XP laptop recognized it (via USB 2.0). Any suggestions would be appreciated. TIA.