Summary: You will need to use Disk Utilities (in your utilities folder) to reformat this drive for Mac journaled. It's easy and takes less than 5 minutes. Only gave 4 stars because the drive light is at the top back of the case not on front where it belongs. There is no off switch on these drives but they sleep just fine with low watt draw. Also there is no extra usb port for an out and daisy chain. Still seem to be great drives for the money. I have two, one 2tb and one 3tb.