Hey, I have a lacie 200 GB FW 800 external hard drive that is a few years old. When I installed os x 10.3 a few years ago things started to go wrong. For some reason it doesn't mount anymore with firewire 800 and only mounts when I plug it into my firewire 400 port. When I try to mount it using firewire 800 it acts like it is about to mount but then doesn't show up on the desktop. When I open disk utility it says nothing about the drive and when I open system profiler it thinks nothing is connected to my firewire port. For a while I thought that my firewire 800 port was bad; so I just used the 400 port, however, I just tried a new lacie FW 800 drive with my 800 port and it worked fine. So then I started testing things to see if I could get my drive to work. I formated my drive with disk utility (I even wrote zeroes to all the sectors) but still it didn't work. I then plugged in the new HD to my computer via FW 400 and daisy chained the old drive via FW 800 to FW 800 and it worked. This means that the drive's FW800 port must work. However, when I just used the old drive via FW 800 it doesn't work. I haven't tried plugging the drive into another computer's FW 800 because I don't have another one to try. If anyone can help with this that would be greatly appreciated. Thanks.