I just bought a FW/USB 250GB external Maxtor HD and it wouldn't partition or erase on my G5 dual 1.8MHz. So I took it into work and the techs formatted it on a PC and then partitioned and erased it on a Mac. Then when I got it home, it gave me the same trouble again when connected to my G5! First I tried FW, then USB, and when preparing to send it back for an RMA, I plugged it into the FW port again and it mounted! Then I copied my iTunes and iMovies to it, and it "seems" to be working, but I am suspicious of it. I will keep it for a while and try to use it regularly. Maybe it take a little coaxing to get an external HD to work.