I'm running a 2012 Mac Pro with an internal SSD. It was partitioned with a Windows 7 installation via boot camp and was running fine. However, a few days ago I went to change the startup disk and received: "You can’t change the startup disk to the selected disk. The bless tool was unable to set the current boot disk." Went to reset my partition on the SSD and Bootcamp Assistant tells me the Mac doesn't support Bootcamp. I'm at a loss, any advice?