MBP stubbornly hangs while booting

(Robert Brenstein) #1

I Googled, I searched Apple forums, but I can’t find anything relevant enough, so I thought to seek the wisdom and experience of this group.

MacBook Pro 15-inch early 2011 with 16 GB of RAM running El Capitan

I love that computer and it has been my main workhorse for years. During the last year, it had several instances when the screen would suddenly go white or black and computer would stop responding, while I was working on it. After forced shut off, I could reboot. On occasion, the computer would hang up during booting. However, until now, I could always start from my emergency USB drive, run checks and then restart normally. Nothing ever found except occasional corruption of drive directory, nicely fixed by DiskWarrior.

Past few days, the computer fails to boot. The boot progress bar gets to almost 2/3, and then
a. I see a stripe of funky lines about 1 cm high in the upper part of the screen, the rest of the screen turns white, and after some 10 seconds computer self reboots
b. the screen turn white, some times black, even more seldom blue, the computer sits for like 30 secs, then reboots (usually, sometimes it just sits like that for ever)

Holding D at boot, brings hardware diagnostics fine but even running the extended check a few times finds no problems.

Holding shift to boot in safe mode does the same as above but never self reboots.

Holding cmd-R does the same when the boot progress bar is about half way. No self reboot.

Holding cmd-V to get verbose boot, the last entry is appleLPC:notify…

Resetting PRAM reduced frequency of hang-ups, that is computer reboots self more often.

Booting from a USB stick (holding the option key to select the boot devices) does the same as booting from the main drive. The USB drive is a Yosemite-based drive with utility tools created by DiskToolPro.

The moment the computer gets weird during boot is the same when during normal boot the screen blinks (progress bar disappears for a second, then comes back).

Any ideas?


(David Rostenne) #2


I spotted this article a few days ago, maybe it will help!

Diagnosing a Mac which can’t complete booting

My guess is corrupted firmware of some kind that that hardware diagnostics does not find.

Have you taken it in to Apple yet to see what they say?



(Robert Brenstein) #3

Firmware corruption is implied by the diagram, but, why would firmware corruption show itself off randomly once every few months or weeks? No, I haven’t got the laptop to Apple people yet. That takes time and I am working on a deadline.

(David Rostenne) #4

Hmm. Good point… software corruption would be more likely to be consistent. My second guess is a hairline fracture somewhere on the board… if it’s moved a tiny bit nothing works right and a bit the other way and it works fine.

Neither will be easy to catch!

Does the laptop have more issues when it has been off for a while, or when rebooting? It might be a temperature thing that is affecting the fracture.

At this point i’m just guessing though!



(Robert Brenstein) #5

Right now, I see the same whether the computer is hot or cold. I think it has been heating internally higher than before but that is just a feeling. I even installed app that cranks up fans. I carry this laptop a lot in a backpack, so a fracture should cause a lot more trouble, me thinks. The freeze-ups occurred always when I was working, so the computer was stationary. A few times, I was not even typing but just looking at the screen. I thought it could be the graphic card since there are always display artefacts, but it works fine when running hardware diagnostics or switching the target disk mode. Also during the initial part of the booting.

(Jeffrey Jones) #6

That model was subject to a long-time Repair Extension Program, now expired. Your issues sound like it could be the one addressed by that program. If so, the logic board would need to be replaced.

Here is some info:


(frederico) #7

The issue you describe typically will not be exposed by the consumer version of the Apple Hardware Test; if you search the dark places of the web, you can find the more in-depth Apple Service Diagnostics utilities that will indeed expose the exact problem. That said, as indicated above, you just have one of the tens of thousands (millions?) of badly manufactured and assembled Apple products of that era, and that test is purely academic.

I have successfully resurrected at least four 2011-2012 models exhibiting exactly what you describe by carefully tearing it completely down and properly cleaning and reinstalling thermal paste (Arctic Silver) to both the CPU and GPU, along with an extreme cleaning of dust from the fans, heat sinks/thermal radiator tubes.

However, most of these units require an additional step in which you must reflow the solder for the GPU pins. If you’re so inclined, and have a decent heat gun (or a super-good hairdryer), it’s isn’t nearly as terrifying as it sounds. I couldn’t find my favorite link to a how to, but here’s a decent guide from Tom’s http://www.tomsguide.com/faq/id-3678804/fix-macbook-pro-graphics-card-issues.html

You can use the above guide to simply try the thermal paste-only method; it takes around 30 minutes to try and test if you’re comfortable with tiny screws and cable release methods — be sure to also peruse the ifixit guides, which offer better details on how not to destroy your cable connections by using the proper release mechanisms.

Now, that said, but for a couple of crashes you describe, most people experiencing similar issues are indeed bitten by the aforementioned mostly-fatal flaw in the logic board, which renders the discrete GPU useless; but if you have no inclination for the heat gun surgery, you can still work around this by “permanently” disabling the discrete (Radeon) GPU, and running only the integrated (Intel) GPU. This will suck if full video performance (h.264 video, games, etc), GPU-dependent apps (e.g., video/audio encoding) or external displays are part of your workflow, but can at least let you hobble along until you decide what you want to do long term.

For some versions of this software workaround, you can simply install the free gfxCardStatus utility (assuming you can get it to boot long enough to install), and permanently disable the Radeon via software/NVRAM setting; but since you indicated some freezes/panics/sudden-reboots that didn’t sound like they happened during a dynamic shift from integrated to discrete GPU, I’m going to assume this won’t work, but it’s worth a try. https://appletoolbox.com/2010/05/utility-allows-macbook-pro-mid-2010-graphics-switching/

A slightly more drastic measure is to kill the Radeon kexts entirely, and also costs nothing to try; again, I couldn’t find my favorite link, but here’s an annoyingly wordy video that uses the correct instructions:

Be sure to just copy out the correct CLI instructions from the video description.

Finally, many good Mac shops charge about $125-$150 to do this repair for you; alternatively, you can often grab just a logic board for as low as $75 on eBay if you’re patient ($150-$200 if you’re not). Just be sure the seller offers enough of a guarantee/warranty that you have adequate time to install and stress-test.

Happy to assist further if required; if you’re in the Boulder area, I can hook you up.



(frederico) #8

PS: chances are pretty good that your system is badly hammered, and you may have to perform a system restore to repair unrelated damage (e.g., wasted kextcaches) that could be causing other types of panics; if possible, do a clean install to another drive (or make a spare volume on your internal drive, if there’s no other option) and apply the software fix there first. If that resolves the crashing, apply the same fix, as well as the precautionary system restore to your current installation.

PPS: for anyone wandering past this thread with a 2008-2010 model, you have an entirely different hardware defect (a $0.50 resistor gone bad; easily replaced), but the gfxCardStaus utility will give you the same outcome if you’re happy enough with hobbled performance.

(Robert Brenstein) #9

Thanks guys for the extensive input. This computer in fact underwent a repair under the free exchange program. That was a few years ago, so I sort of forgot about it. I just took the drive out. It had indeed some corruption, but DiskWarrior fixed it. I just booted another computer from that drive connected through USB. Darn slow but it is working, so I can deal with the software solutions. I will follow other suggestions shortly.