I bought a 500GB My Book Pro Edition external hard drive (HD). Link I am using it with my MacBook Pro. I used USB 2.0 connection, which worked and installed the two softwares provided. I connected the HD using firewire 400 and it worked, but when I connected the HD using firewire 800, it did not work. I tried a few simple changes, but nothing helped. Not working means not being identified by the OS and not showing in the disk utility. Basically, USB 2.0 and Firewire 400 worked, without the need of any installation. Firewire 800 did not work at all. Is this a normal or do I need a special installation technique or could this be a problem with my Mac? Your help is greatly appreciated. Thank you in advance.