Hey all...I've got a bit of a head scratcher, so I'm reaching out here and hopefully someone can offer some insight on my problem. I recently upgraded my 2012 Macbook Pro to an SSD. My girlfriend was supposed to take my old 750GB hard drive for her own 13-inch 2012 MBP, which is where the problem comes in. I cloned her original hard drive with Super Duper without issue, except it will not be recognized or boot from the internal HDD bay. It is, strangely enough, recognized and bootable over USB through my SATA/USB cable. The drive, which up til a week ago was working just fine in my own MBP, won't boot internally from the original machine either. I wiped and reckoned the drive again using Super Duper and once more through the recovery partition using OS X's disk utility to no avail. If I look at the drive over USB, everything is there that should be there, but the computer won't recognize the drive if it's installed internally. FileVault was enabled for the first cloning, but I disabled it for the subsequent attempts. There's no firmware password on the MBP and as I said, it was readable by my own MBP right up until I removed it last week. Her original drive and my new SSD are both bootable from the internal bays in both machines, so I'm confident the drive cables aren't the issue. I don't think it's possible, but I'm not discounting the idea the drive could've been damaged in the few days it was out and about before I got to cloning her drive, but it was sitting quietly in the box the SSD came in. So, any ideas on how I can get this drive up and running? Let me know if there's any more information I can provide.