I'm having the exact same problem. Tech support (australia) was 100% useless, I was expecting more (after reading other, albeit, USA-based posts). I want to use the drive on THIS computer, which meets the drive's requirements (Powerbook G4, OS X 10.4.11, up to date), not another one to "see if it works". If it meets the system requirements, Plug-N-Play should work in exactly that order. Have done the apple+option+p+r reset to no avail. Borderline returning the product to buy something that doesn't have the requirement of me spending 45 mins on hold for 0% help.