Chosen Solution
I was using my laptop and everything was fine. I’ve been running 2 displays as well for the past week. So yesterday while the computer was running I just closed the lid (put the screen down) but today when I came back the computer wouldn’t start. I powered down by pressing the power button and I could hear a click. Then power it up and it chimes and goes to being shut down. When I close the lid the power light comes on. When open it, it turns off. I took the battery out and plugged it back in. Same thing. Oddly enough a couple of time before the battery removal, the computer was going into recovery assistance mode and it was the only time I got the screen to work. But when I chose start up disk and restarted it, it was going back to the issue. I have the 750gb HDD and it’s only 25% full.
You’ll first need to replace the battery as clearly its worn out! MacBook Pro 15" Unibody (Early 2011-Mid 2012) Battery and here’s the guide MacBook Pro 15" Unibody Mid 2012 Battery Replacement The reason you are encountering drive issues here has to do with the weak battery is not able to sustain the system when you put it into sleep mode. Basically the RAM and the drive space become corrupted! After you replace the battery and its fully charged, Make a TimeMachine backup so you can restore your stuff. Make a bootable external drive with the needed OS installer so you can reformat your drive and install a fresh OS onto it. Then restore your stuff. Using TimeMachine makes sure any corrupted file gets fixed or marked as bad. If you tell us your OS version we can give you a bit more on how to create the bootable disk and get a working OS installer file If you’ve got an old macOS install image, it will probably stop working today
