Like others here, I am a long-time Mac user. Stidwell's instructions are a good starting point, but I've been through 2 shrink-wrapped boxes of this drive, and while the USB interface worked reliably, the Firewire (1394) did NOT always work. What is so odd about this drive is that if one unplugs the power and usb cord, and plugs in the firewire cord FIRST, then the power, the drive will often mount. But there were times I could not replicate a proper procedure to have this mount reliably EVERY time. This on an intel Mac mini and an older PPC G4 Cube. I repair Macs for a living, so I don't mind adventures with equipment, but for the general consumer, I would stay away from this particular model. Seagate still makes top notch product, but this model is not for the general Mac user.