Using kit from iFixit, I added 2nd HDD (Seagate Momentus XT ST750LX003 750GB). Installation seems fine, Mini recognizes drive. When I try to format, using Mac OS Extended (Journaled), it begins, then fails with the following error: Disk Erase failed Disk Erase failed with the error: File system formatter failed. Partition information then shows the name as diskOs2 with the Mac OS Extended as the type. I can change the number of partitions, but it still gives the same error when I try to format one of the partitions. Any ideas appreciated.