In the past three days, I noticed that when I started my new Mac Pro there was a repeated clicking sound while it was booting up. The first couple of times it lasted about 4 clicks and then started up normally. Today, It clicked for about 10-15 times and then finally booted up but a window came up that said that a hard drive was not able to be recognized by the computer and offered me the option to initialize it. When I did, disk utility came up and I noticed that it was the media drive I have in bay three that was not accessible, but it did not allow me to do any erasing, partitioning, verification etc. because all the options were grayed out for that drive. I restarted the computer (again with repeated clicking) but this time the media drive was not even visible in disk utility and no warnings or options to initialize the drive appeared. I opened the case and removed and reseated the drive and tried again and got some clicking and then the drive appeared in Finder. I ran disk utility to verify and repair the drive but it reported no problems. Can anyone please advise on what might be wrong? And where I could find some utility that will actually check the drive to see if it is faulty? I have 4 drives in the computer. Is is OK to switch bays with the drives to test whether the drive or the bay might be at fault? I don't want to damage any other drives if putting it into a faulty bay might cause problems. Is there any utility that can be used to check if the bay itself is faulty? Thanks for any advice.