I just picked up a 2012 Quad core and want to get a new SSD and some more RAM in it... and so the journey began I picked up THIS DRIVE along with the Data Doubler Kit Followed the install video, build it back up and ... nothing. Drive not recognized in Disk Utility program or with Terminal diskutil list command. Now, I know this isn't exactly unique and after searching around a bit I found a few things that could fix it. I take it apart again and connected the NEW drive with the NEW ribbon to the OLD (original) SATA connection. The drive was recognized, I formatted it. Take everything apart again and try to connect the OLD drive with the NEW ribbon to the NEW SATA connection The drive was recognized. Nice. At this point I have confirmed that both the NEW and OLD drive are operational. The NEW and OLD ribbons are operational. The NEW and the OLD SATA ports are operational. Should be good to go and based on what I was reading a lot of people ended up putting the NEW SSD drives into the bottom (closest to black twisting bottom of mac mini) bay with the OLD ribbon (the size and shape of them means the ribbons only work with their intended bay) and putting the OLD platter drive into the top bay using the NEW ribbon. Boot that up and ... Only the OLD platter drive is recognized! I have already established the NEW SSD is operational and has been recognized using both the connected OLD ribbon AND the OLD SATA port ... wtf can be going on? I've seen people have issues with it not being recognized and having to do a SATA to USB external connection, but I have already had it recognized and formatted using Disk Utility. Generally when using this sort of process of elimination I can pin point a hardware failure somewhere, but EVERYTHING has proved operational using the different drive, port and ribbon combinations. I should also mention that I have at various times booted into recovery using the old platter drive, booted into internet recovery with just the new SSD in and no platter drive, and booted into a USB recovery when I had both drives in as well as just the SSD drive in ... in all instances the only time I was able to recognize the SSD is when it was alone (no platter drive) and connected to the OLD SATA port. I'm at a loss ... any insight is VERY appreciated!