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2015 Macbook Pro won't boot OS, need helping diagnosing problem

abearatemyparents

macrumors newbie
Original poster
Sep 7, 2020
5
0
I have a mid-2015 Macbook Pro that recently got stuck in a restart loop. The screen went black while I was using it and it started back up, booted fine, and stayed on for a few minutes before doing it again. Eventually it got to the point it wouldn’t even boot the OS. The power cable was frayed and the battery had been starting to expand but up until then everything had been working so I put off dealing with either issue, so when it first happened I thought maybe it was a power issue. Replaced the power cable, no change, removed the battery, same problem.

It will turn on fine and can get to the login screen, if I don’t do anything it will stay there indefinitely, but if I enter my password it starts loading the OS and then crashes. Same thing when I try and boot in recovery mode. It will connect to Wifi and load internet recovery mode, but after it finishes loading and goes from the globe to the Apple logo, it again starts to load and then crashes. I can get to the start up manager, where again it will stay indefinitely, but if I try loading my Windows partition it does the same thing, starts loading and then crashes and restarts in an unending loop. It can successfully run diagnostic mode, but with the battery out all it tells me is that no battery is detected (error code PPT001), and if I plug it in it says the battery isn’t charging correctly (error PPP003), it gives no other error messages and the only option either way is to either run the test again or start up in recovery mode, which it of course is unable to do.

I’ve been told this may suggest the logic board is failing, or possibly an IO board cable, but from what I’ve read it also sounds similar to what happens when the hard drive cable is bad? At this point I’m considering taking it to a third party repair shop for diagnosis, but if it’s as simple as a bad cable I’d rather just swap out then spend the time and money. Is there any way I can better determine what the issue might be?
 

JMVB

macrumors regular
May 16, 2016
131
20
Happens to me in a 15" 2012 non retina model, and was a bad RAM.

Then, had a very similar problem in friend mine 12" 2017 macbook, solved cleaning meticulously with compressed air duster.
 

abearatemyparents

macrumors newbie
Original poster
Sep 7, 2020
5
0
Happens to me in a 15" 2012 non retina model, and was a bad RAM.

Then, had a very similar problem in friend mine 12" 2017 macbook, solved cleaning meticulously with compressed air duster.

Thanks for replying. I cleaned it pretty thoroughly when I was taking the battery out, but was planning to take another look just in case.

Is there any way I can test the RAM? I don't want to start buying new components until I have a better idea of which one is causing the issue.
 

4sallypat

macrumors 65816
Sep 16, 2016
1,379
1,118
So Calif
Apple Diagnostics
  1. Disconnect all external devices except keyboard, mouse, display, Ethernet connection (if applicable), and connection to AC power.
  2. Make sure that your Mac is on a hard, flat, stable surface with good ventilation.
  3. Shut down your Mac.
  4. Turn on your Mac, then immediately press and hold the D key on your keyboard. Keep holding until you see a screen asking you to choose your language. When Apple Diagnostics knows your language, it displays a progress bar indicating that it's checking your Mac:
 

abearatemyparents

macrumors newbie
Original poster
Sep 7, 2020
5
0
Apple Diagnostics
  1. Disconnect all external devices except keyboard, mouse, display, Ethernet connection (if applicable), and connection to AC power.
  2. Make sure that your Mac is on a hard, flat, stable surface with good ventilation.
  3. Shut down your Mac.
  4. Turn on your Mac, then immediately press and hold the D key on your keyboard. Keep holding until you see a screen asking you to choose your language. When Apple Diagnostics knows your language, it displays a progress bar indicating that it's checking your Mac:

Thank you for copy/pasting half of the instructions, but as I stated, running diagnostics just tells me either the battery is unplugged or the battery is not charging and provides no other helpful information.
 

Brian33

macrumors 6502a
Apr 30, 2008
917
98
USA (Virginia)
I'm not sure if it would help any, but it might be interesting to see if it will start in single-user mode (apple page). You'll get just a command-line interface -- no gui. Maybe that would rule out/indicate a graphics problem.

Also could try safe mode. I think prevents loading of login items and some kexts. (safe mode)
 

abearatemyparents

macrumors newbie
Original poster
Sep 7, 2020
5
0
I'm not sure if it would help any, but it might be interesting to see if it will start in single-user mode (apple page). You'll get just a command-line interface -- no gui. Maybe that would rule out/indicate a graphics problem.

Also could try safe mode. I think prevents loading of login items and some kexts. (safe mode)

When I try and start in safe mode nothing happens, it proceeds to the login screen normally and then if login it crashes.

Single user mode appears to load, I see the command line stuff flashing on screen, but again after I try logging in it crashes.
 

Brian33

macrumors 6502a
Apr 30, 2008
917
98
USA (Virginia)
Single user mode appears to load, I see the command line stuff flashing on screen, but again after I try logging in it crashes.
If it's booting to single-user mode OK, when you hit enter and it should just give you a command line prompt. There's no logging in. So I assume you mean after a "reboot" command and then logging in, it crashes.

It's interesting that it seems work in single-user mode. That does load the OS, just not the graphical GUI part. It seems like evidence that the problem is not bad RAM. But perhaps it's just not trying to use the bad part of the RAM...

One of the other ideas was that it was a bad hard drive cable, but the booting to single-user mode argues against that. Once in single-user mode one could verify the filesystem with the "diskutil" command.

If you're familiar with Terminal.app and command lines, you can do a lot in single-user mode (including getting files off of it, if you need to). There are probably command-line memory test programs. (Here's one that creates a bootable USB/flash drive: https://www.memtest86.com/download.htm; it's a bit cumbersome to do it in macOS, but easy if you have a Windows machine handy. There are probably other mem test programs available, too.)

It still seems possible that it's not a hardware problem, but something wrong with the macOS installation. You could try booting from an external HDD on which you'd installed macOS from another Mac, to see if it has the same crashing behavior -- if so I would conclude a hardware problem.

Best of luck to you.
 

abearatemyparents

macrumors newbie
Original poster
Sep 7, 2020
5
0
If it's booting to single-user mode OK, when you hit enter and it should just give you a command line prompt. There's no logging in. So I assume you mean after a "reboot" command and then logging in, it crashes.

It's interesting that it seems work in single-user mode. That does load the OS, just not the graphical GUI part. It seems like evidence that the problem is not bad RAM. But perhaps it's just not trying to use the bad part of the RAM...

One of the other ideas was that it was a bad hard drive cable, but the booting to single-user mode argues against that. Once in single-user mode one could verify the filesystem with the "diskutil" command.

If you're familiar with Terminal.app and command lines, you can do a lot in single-user mode (including getting files off of it, if you need to). There are probably command-line memory test programs. (Here's one that creates a bootable USB/flash drive: https://www.memtest86.com/download.htm; it's a bit cumbersome to do it in macOS, but easy if you have a Windows machine handy. There are probably other mem test programs available, too.)

It still seems possible that it's not a hardware problem, but something wrong with the macOS installation. You could try booting from an external HDD on which you'd installed macOS from another Mac, to see if it has the same crashing behavior -- if so I would conclude a hardware problem.

Best of luck to you.

First let me just say thanks for actually trying to help! It's very much appreciated.

I'm not familiar with single user mode, and wasn't sure what it's supposed to look like, so I may have inadvertently misspoke. When I hold cmnd + s, white text on black flashes briefly before going to the Apple logo and then the login screen, if I try and log in it runs through more white text on black and then just goes black and restarts, I never have a usable command line.
 

Fishrrman

macrumors Core
Feb 20, 2009
20,521
7,290
If you have a brick-n-mortar Apple Store nearby, take it to them and see about getting the battery replaced. Cost should be $199. IT'S WORTH IT for the new battery.

BEFORE going further, explain the non-starting problems. Perhaps they can diagnose this before the battery change...
 

Brian33

macrumors 6502a
Apr 30, 2008
917
98
USA (Virginia)
Ah, I'd forgotten that you must have Filevault enabled -- that's why you get the Login screen even when trying to boot in single-user mode. So that didn't work, either.

I can't think of what else to try except, as Fishrrman suggests, inquiring at an Apple Store. I'd be skeptical that a new battery would solve the startup crashing problems, but it would be interesting to hear what they said.
 
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