MacBook Pro mid 2012 won’t boot

1. Reset SMC by following the directions applicable to your MacBook Air here ➔ How to Reset SMC. If that does not solve things then-
2. Reset NVRAM/PRAM by following the directions applicable to your MacBook Air here ➔ How to Reset NVRAM/PRAM. If that does not solve things then-
3. Enter ➔ Safe Mode and see if the screen issue still exists in Safe mode. Log out of Safe Mode and then reboot computer. If that does not solve things then-
4. Finally if none of the above works then you can enter ➔ macOS Recovery Mode and reinstall the macOS and see if that solves it.

More than likely step 4 is what you will end up doing if the first 3 do not work.

Axel F.

Axel,

"More than likely step 4 is what you will end up doing if the first 3 do not work." You should read this again. Sort of obvious that after step 3 comes step 4, then step #; well, you get the point.

Kappy,

Good Point.

What I attempted to convey was that, More than likely step 4 will work to solve the issue vs the first 3.

Not sure what I was thinking when I typed that line in response to the original post. Good catch.

Axel F.

Non-Retina 13-inch MacBook Pros, especially the 2012 version, have been nearly bulletproof but for one thing: the hard drive cable.

It is better described as a super-thin flexible circuit board. It suffers from routing across sharp metal edges on the chassis. With 3-5 years of the vibration of normal use and transport, its insulation can chafe and cause big issues. Symptoms of a worn cable can mimic a failed of failing hard drive.

If the steps the others have provided do not help, consider a new cable. They are available, cheap (~US$15), and easily installed by a novice users.

Install video here: https://eshop.macsales.com/installvideos/macbookpro_13_unibody_mid12_hard_drive_cable/

Where I bought my cable: Apple Hard Drive / SSD Cable For 13-inch MacBook Pro (Mid 2012) main drive bay