First let me say that I am a computer numbskull. I first set it up on a PC. That crashed and I now have a Mac. I would completely reformat it, but there are files on it I need. I don't know how it was set up, I just did what it told me. When I do the First Aid thing with my Mac now, it shows me a partition bar that appears to be all Linux partitions. I hope that answers your question.