Chosen Solution
My 13-inch, Mid 2012 MacBook Pro was being very temperamental a few weeks back (any open apps would freeze immediately upon startup). First Aid indicated the volume could not be verified, gave a file system check exit code of 8, and indicated that the First Aid process had failed. At one point I ended up on a screen to Choose Startup Disk. I selected the only available disk received an error: “You can’t change the startup disk to the selected disk. The bless tool was unable to set the current boot disk.” I attempted to install OS X Mavericks and received the error: “Volume contains a macOS or OS X installation which may be damaged.” I somehow ended up restarting in some sort of terminal mode. Lots of info but the bits that look concerning indicate “failed to locate mount-on path” and “failed to mount”. I somehow managed to reinstall the operating system (I don’t recall which version but I do NOT believe it was Catalina). It worked fine for 2-3 days. Now I cannot get it to fully boot or really do much of anything. For both a regular startup and startup in safe mode it would not progress the apple logo with a full progress bar (I let it go for 2 days). I reset the SMC and got the same thing. I attempted to reinstall the operating system again but the installation would not progress at all. Apple diagnostics: ran with laptop unplugged and saw “A 45W power adapter is connected. This system requires a 60W power adapter to charge properly.” Also, “There may be an issue with the power adapter.”Plugged laptop in and no issues were found. After apple diagnostics it restarted in MacOS and I was able to choose the language It looked like it was going to hang up on “Examining volumes…” but it finally opened to macOS Utilities. Ran First Aid on the sole disk image, macOS Base System. Volume could not be unmounted but everything else looks good, exit code was 0. Ran First Aid on the three internal volumes (no, I don’t know how I ended up with three and no, I do not need three). It failed for all three, indicating the volumes could not be unmounted and “the repair cannot be performed because one or more volumes are mounted. : (-69565)” I found an article that recommended rebuilding mbr_cache (https://appletoolbox.com/macbook-stuck-a...). That seemed to go well but it’s been no progress was made after 2 full days of a black screen with a white spinning wheel so I shut it back down and let it start up normally. We’re back to a white screen with the apple logo and a full progress bar. Any suggestions? I am NOT concerned about recovering any data or programs but I would really like to have a functional laptop, especially considering it’s not even 6 years old.
You are hitting a classic case of a bad HDD cable! Your Hard Drive Cable Is A Ticking Time Bomb Here’s the needed part MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable and the guide to put it in MacBook Pro 13" Unibody Mid 2012 Hard Drive Cable Replacement Don’t forget to put a strip of electricians tape on the uppercase. And you don’t want to fold the cable as that also damages it! Instead find an old BIC ball point pen to take the ink straw out use it as a forming brake to create a nice arc where the cable needs to bend around a corner.
