Boots halfway then reboots

Nermal

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Original poster
Staff member
Dec 7, 2002
18,690
1,185
New Zealand
Hi everyone,

My dad's just brought his machine around to me because it's not booting anymore. The boot chime plays, the Apple logo appears, and the progress bar gets to the halfway point then the screen turns solid silver (no mouse) for about 30 seconds. Then it goes completely black for another 30 seconds. Finally, it reboots itself and the cycle continues.

Booting with Cmd-V doesn't give anything of value; it all looks about normal, then it all goes silver again. Cmd-S works as expected and I'm able to run fsck (no errors) but I don't know what else to try. Cmd-Opt-R also eventually results in the silver screen, once it's downloaded the necessary files.

I'm not finding many reports of this issue. One suggestion I found was that it could be a failing hard drive, but I tried swapping the drive and it didn't help. The battery also looks fine; it doesn't appear to be a power issue. An SMC reset has also had no effect.

I'm aware of this, but the symptoms listed don't mesh with what's occurring here.

Does anyone have any suggestions about what could be going wrong here?

System is a 15" 2011 MBP.
 

vertical smile

macrumors 601
Sep 23, 2014
4,018
5,215
I have seen similar issues with failing or corrupted boot drives and failing GPUs.

Did you try booting into recovery mode (command +R) or run a HW diagnostic test (hold D), or safe mode (Shift)?

If recover mode doesn't work, try doing command+alt+R for internet recovery mode.
 

happyslayer

macrumors 6502a
Feb 3, 2008
912
412
Glendale, AZ
You've certainly tried everything to troubleshoot that I can think of, but my first thought after you described the problem is that this is video card/chip related. It sounds like it's getting to the point where it would initialize the video to draw the desktop and then can't so it chokes/freezes. I'm honestly not sure how you could test this, though. If you have an Apple Store you could bring it in but I am not sure if they would charge to check it, or if it is worth it to pay for the repair. You might have better luck checking on eBay for a similar (possibly newer) model instead. Good luck
 

Nermal

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Original poster
Staff member
Dec 7, 2002
18,690
1,185
New Zealand
Did you try booting into recovery mode (command +R) or run a HW diagnostic test (hold D), or safe mode (Shift)?

If recover mode doesn't work, try doing command+alt+R for internet recovery mode.
I didn't try "normal" recovery, but Internet recovery didn't work. I didn't know about diagnostics so I'll give that a go (dad's gone home now and taken the computer with him, but I'll give it a try if I get it back).

It sounds like it's getting to the point where it would initialize the video to draw the desktop
Ah. Well, that does make sense. But at the same time I wouldn't have thought that the boot screens would work, but then again these are complicated machines!

I'm honestly not sure how you could test this, though. If you have an Apple Store you could bring it in
None in the whole continent, I'm afraid! Of course there are third-party places but they'll charge an arm and a leg.

Edit: Found some steps for disabling the AMD drivers, which might help.
 

Fishrrman

macrumors P6
Feb 20, 2009
17,444
5,657
A 15" 2011 MacBook Pro?

I suggest you do some reading on the term "RadeonGate".
That's referring to the failure of the discrete GPU in these MBP's.

Not worth paying to "fix" any more.
There -is- a way to permanently disable the discrete GPU. There are long threads in this forum about how to do that. Seems like you've found that out for yourself.
That's what I'd try.

If disabling the discrete GPU won't work, it's probably time to be looking for a new MacBook Pro...
 

jorgk

macrumors member
Mar 20, 2013
88
5
I had a MBP 15" 2011 with the dGPU problem - gave precisely those 'symptoms'.

Check the long threads on how to inactivate the dGPU:
https://forums.macrumors.com/threads/force-2011-macbook-pro-8-2-with-failed-amd-gpu-to-always-use-intel-integrated-gpu-efi-variable-fix.2037591/

There should be a similar thread with the "GRUB" solution.

If adventurous, try this:
https://forums.macrumors.com/threads/permanently-disable-2011-15-17-macbook-pro-dedicated-gpu-gmux-ic-bypass.2134019/

But all in all, get a new MBP or get hold of a logic board of the corresponding mid-2012 model and switch that in (ideally, also change to a BT4 airport card). That makes it into a mid-2012 that run's way less loud than the jet engines (aka fan's) of the 2011 models when trying to cope with the dGPU heat.
 
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Audit13

macrumors 601
Apr 19, 2017
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Toronto, Ontario, Canada
But all in all, get a new MBP or get hold of a logic board of the corresponding mid-2012 model and switch that in (ideally, also change to a BT4 airport card). That makes it into a mid-2012 that run's way less loud than the jet engines (aka fan's) of the 2011 models when trying to cope with the dGPU heat.
It a good solution if you are comfortable with doing the swap yourself:
https://www.ifixit.com/Answers/View/93540/MacBook+Pro+2011+to+2012+logic+board+swap#answer339758
 

Nermal

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Original poster
Staff member
Dec 7, 2002
18,690
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New Zealand
Edit: Found some steps for disabling the AMD drivers, which might help.
This didn't work; it kept saying "operation not permitted" when I tried to move the drivers out of /System/Library/Extension despite being logged in as root.

BUT...

"nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00" seems to have done the trick :)

Thanks for the tips. If it dies again, it dies, but it does appear to be working so far.