I have 4 internal hard drives inside my Mac Pro. Three of them are 2Tb Hitachi drives and the other is the internal drive that came with the machine. One of my drives will not unmount - it says it might be in use by another application. I have tried Disk Utility and Drive Genius with no luck. It is being backed up by Super Duper so I know I have a copy. There is approximately 1.1 TBs of data or about 56% full. It is also not copying files in or out easily. I dragged over 4 audio files of maybe 80 MBs in size and it would not copy them into a folder. But when I dragged them to the icon, it copied in under a second. I must also tell you that Spotlight is endlessly indexing and I cannot turn it off. I have dropped it into Privacy, I have used Spotless to turn it off and even used the sudo mdutil on/off in Terminal to try to stop the indexing - no luck. I cloned another external 2 TB firewire drive and Drive Genius can unmount and rebuild that without a hitch. So it can copy but there is obviously something wrong here. Update: I've started off of another system drive and used both Drive Geius and Tech Tool 5 to rebuild and clean up my internal system drive - no change. I tried to re-format the offending drive and I was not able to - got an error code of -1407. Then I approached it differently. I own a NewerTech VoyagerQ which I can put bare drives in. I removed the drive from the Mac Pro and inserted into the NewerTech bay and it appeared as a firewire drive. I ran Disk Utility and it was able to repair it. Then I tried to run Disk Utility again and it wouldn't unmount. It seemed to be okay for a moment but then failed again. I tried the same thing with Drive Genius and it would not unmount - very strange. So, I cannot even re-initialize the drive ... and yet it works (sort of) not enough so that I could fully trust it. By the way, it's only 2 months old. I'm at my wits end - got nothing else to try - any ideas?