MacOS completly useless or bricked after bootcamp install! Please help!

[diesto]

Hi. So I installed bootcamp on my MBP 2012 A1286. Windows works just fine, but I cannot boot into MacOS. Endless loop. I have tried PRAM, NVRAM, SMC reset. I have also tried recovery mode, internet recovery and the internet recovery to factory (snow leopard). I also tried to swap out the RAM and SSD to another mac. The RAM and SSD works just fine in the other macbook. But still issue occurs with a HDD inside. I also tried to reapply thermal paste.
When I did a USB install I got this error screen. This is the only information I have managed to get.. I desperatly need help so would greatly appriciate any response with suggestions! Thanks alot!

 

[barbu]

Can you use the startup disk control panel in windows to choose the Mac partition?

 

[diesto]

I cant check atm since I tried to delete Windows from the SSD to see if that solved the issue. I was however able to see three disk drives by using diskutil in cmd. I have another SSD with windows installed on that I can use. Would should I do if I were to see the Mac partition?

 

[satcomer]

I cant check atm since I tried to delete Windows from the SSD to see if that solved the issue. I was however able to see three disk drives by using diskutil in cmd. I have another SSD with windows installed on that I can use. Would should I do if I were to see the Mac partition?

Then it sounds like you borked your OS X partition!

 

[Fishrrman]

You may have A LOT of work ahead of you to get that Mac stuff back (if it's still there).

If you put the MacBook into my hands, here's what I'd try.

You will need AN EXTERNAL USB3 DRIVE for what we're going to do.
Actually, you may need TWO external drives.

1. Boot to INTERNET RECOVERY
Command-OPTION-R
This is NOT THE SAME as "the recovery partition".

2. You'll need your wifi password. The internet utilities take a while to load. Be patient.

3. Once the utilities load, connect the external USB drive and open disk utility.

4. IMPORTANT STEP: Go to the view menu and choose "show all devices"

5. Now look at the list on the left. You want to locate the external USB drive.

6. Click on the drive and click "erase". Choose "APFS with GUID partition format" (because I'm thinking the OS installer will want to install Catalina).

7. Erase the drive and quit disk utility.

8. Open the OS installer. Is it Catalina?
(that's the last OS that will run on the 2012 MBP, so I'll guess that's what the Apple servers are going to offer you).

9. Begin "clicking through". VERY VERY IMPORTANT:
When the installer asks WHERE you want to install, choose "show all drives" (or something like that). PICK THE EXTERNAL USB DRIVE. That's where we want the OS to be installed ... NOT onto the internal drive!

10. The Mac will reboot one or more times, and the screen may go dark for a minute or two with no other indications of activity. BE PATIENT.

11. If the OS install is successful, you'll see the initial setup screen (choose your language).

12. Set up a VERY BASIC ACCOUNT with ONLY a username and password.
You DON'T NEED anything more.

13. When this is done, you should get to the finder. You will need to go to the finder preferences and check "hard disks" and "external disks".

14. After doing this, can you see both the USB drive AND the internal drive on the desktop?

OK... if you can get this far...
You are now booted and running the Mac OS from the external drive.
If the Mac OS partition still exists on your INTERNAL drive, you ought to be able to "see it" on the desktop.
Is it there?

IF you can get this far -- come back and tell us, and I'll tell you what to do next.

Good luck.

 

[satcomer]

Is it modern Mac, have tried to reinstall the partition from that!