Summary: I am on my second replacement drive and give up; it's not worth trying for a third warranty replacement. I don't know if it just doesn't like Macs or if it just doesn't work, but it often refuses to mount, and DiskUtility warns me that it's not repairable and to back up all my files.
I have since gotten a 2tb Toshiba solid state back up drive that is wonderful.
27 December 2014
Summary: Arrived non functional. The drive would spin up and start beeping but would not do anything else. I sent it back. To the credit of the seller, very fast refund and customer service. I have since gotten a 2tb Toshiba solid state back up drive that is wonderful.
Summary: Worse external I have ever owned. 1st one died within the year I bought it, replaced it under warranty and the 2nd one did not even last another year. Waste of money and I'll never purchase a Seagate for as long as I live.