Chosen Solution
A couple days ago my hard drive died. I figured it was time for an upgrade and saw that just about everyone recommends SSDs and figured it couldn’t be too hard to replace. Well, I bought a Samsung 860 EVO, installed it, erased and reformatted it to Mac OS (Extended), and then started the OS X install process, which is where everything fell apart. It started an install of Yosemite, which I thought was weird because I’m fully updated to Mojave, with an install time of 16 hours. Which seemed excessive but I didn’t question it. I went to bed with 14 hours left and woke up maybe 8 hours later to see a flashing ? folder. I figured something had gone wrong during the install, it happens, so I erased the drive and started over. And then it happened again. I’m currently on my third try, with 20 hours left on the estimated time (it was 14 last night when I went to bed, not sure why it’s so much longer now).
Is there something I’m missing or forgot to do? I’ve read mid 2012 MBPs have fragile hard drive cables, so could this be a sign that mine is faulty? The laptop definitely recognizes my new SSD and I was able to erase/partition/select it for the install but I guess it could still be bad. I’ve also had problems ever since I installed a new battery from iFixit a couple weeks ago where if I leave the MBP alone for too long it shuts itself off, but that seems to be limited to when I’m not plugged into the charger, so it shouldn’t have happened during my install attempts. I’ve reinstalled the old battery for this new attempt just in case though.
Thanks for any help you may have!
Update (10/24/2018) Let’s try a new Hard Drive cable. What probably happened is you may have bent the cable into a very sharp turn when you installed your new HDD. Or, the problem is that your existing cable can’t keep up with SATA III speeds. You want to create nice arcs where the cable turns, not sharp bends. MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable MacBook Pro 13" Unibody Mid 2012 Hard Drive Cable Replacement
@mrface - You’re hitting a very common issue. The first versions of the 2012 MacBook Pro’s has SATA II (3.0 Gb/s) HDD’s. Later versions have a newer SATA III (6.0 Gb/s) drive. The orginal SATA cable was not rated for SATA III drives so you need to replace it and then to add to this your new SSD drive pushes the I/O even more so! So what to do? You do need to replace the cable and you do need to make sure you’ve got the better one! Here’s the correct cable: MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable Apple P/N 923-0104, and here’s the guide you’ll want to follow MacBook Pro 13" Unibody Mid 2012 Hard Drive Cable Replacement. Besides getting the better cable you also want to improve things a bit as experience has shown us the rough surface the aluminum uppercase wears the cable so we place a strip of electricians tape on the uppercase. Lastly, a common mistake people make is over crease the corners, breaking or damaging the conductive foil wires within the cable. You want an even arch no sharp bends! Good Luck!
