Chosen Solution
Hello, all. I have recently swapped out my hard-drive to an SSD. The first day it ran like an absolute dream but since then it has been awful. Sometimes when powering it on it comes up with the circle with a line through it (I believe this indicates and OS issue?). I used internet recovery initially and then upgraded to High Sierra. If i get it past the circle with a line through it it runs extremely slow and cannot actually perform any tasks. I understand it’s an old machine but would just like to know if there’s anything more I can try before deeming it a lost cause. Thanks in advance!
Sounds like you are hitting a bad HD SATA cable Your Hard Drive Cable Is A Ticking Time Bomb. You’ll want to apply a strip of electricians tape down on the uppercase as outlined and you also want to replace the HD SATA cable as well! Here’s the needed cable MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable and here’s the guide to putting it in MacBook Pro 13" Unibody Mid 2012 Hard Drive Cable Replacement What you also need to be careful with is not damaging the cable putting it in. Don’t crease the cable, the fold will damage the thin foil wires within it! Instead use an old BIC pen ink straw as a forming brake use it to form a nice radius bend in the cable where it needs to get around the corners.
