I bought from Amazon a Seagate 6TB BarraCuda Pro internal hard drive (ST6000M004) which just arrived today, and I find that the threaded holes in the hard drive's case don't line up with the screws of the Mac's mounting brackets. This is a mid-2010 Mac Pro with four drive bays. I had one empty bay and I wanted to put this Seagate 6TB into it, but I can't do it because the HD doesn't have the threaded holes in the right places. This is odd because there is already an older Seagate Barracuda 1 TB drive in this Mac whose mounting holes DO line up with the screws on the bracket. Did I get an oddball drive here, or has Seagate changed all its new drives so that they will no longer match up with the brackets in a Mac Pro tower?