First of all, are the firewire ports on your mac bad? 2 have you restarted your computer and then tried plugging it in? 3 create a new user and login as that person and connect the drive? 4 turn on the drive (if it has a power switch) then plug it in? 5 wait a few moments to see if it recognizes it - this holds very true for OS X, it takes about 30 seconds for my macs to detect mine. 6 plug in the firewire drive then restart the computer. 7 go to system profiler and see what firewire shows when you have it connected. 8 open disk utility and manually mount it. I may have more later on to try.