Here's an article on the problem: http://www.storagereview.com/6tb_hdds_causing_problems_for_system_vendors_but_not_the_way_you_think But the gist of it is that new 6+TB drives omit center screw holes on the drive, and the Mac Pro (and NAS' like Synology) expect to use those center holes. This is a real problem with the Mac Pro as only the front screws can clip on and the drive would wobble dangling downwards. I called OWC as they sell 6TB drives for the Mac Pro, but they have no solution. Does anyone know of some solution. Does anyone sell sleds for the classic Mac Pro to allow you to use these new drives? Thanks for any help.