I have a 2009 MacPro. SSD has the boot and apps from the 2nd Optical Drive. Original 1x4TB drives are in Raid 0 and have all the data (home folder etc). They also have the original OSX and apps which are no longer in use since everything boots off the SSD. I want to erase the 4 raid drives (disconnect raid all together) (data all backed up to a drobo). Use first 3 drives as new storage and the 4th as bootcamp. however, when I try to erase the raid data drives, it says it can't unmount the disk (yes, have no apps running other than disk utility from the SSD apps) Any help appreciated.