Model A1286. Released February 2011 / 2.0, 2.2, or 2.3 GHz Quad-core Intel Core i7 Processor

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Boot loops (black scr) for long time (20 min - hours) before success

I have an early 2011 MacBook Pro 15”, with the following set of symptoms :


On battery, if I press the power on button, I can hear the fans and disk come to life, but there is nothing on the screen, and it the disk powers down again in a few seconds, and then nothing happens. I need to press the power button again to make the machine attempt another start.


On AC power, the behaviour is similar, but the hard disk takes much longer to power down. (I need to stick my ear pretty close to hear this). However, it attempts to power up again by itself immediately. (Disk spins up, IR light on the front blinks). This keeps happening, the screen is black, the faintest switching off of the backlight can be seen on each loop, and takes anywhere from 20 minutes to a couple of hours, when the machine finally lights up. The duration of the attempted restart cycle gets shorter and shorter. After this it boots into the OS and works just fine, and both the integrated graphics and an external display with the AMD graphics turned on run fine as well. Shutting down and restarting works correctly after this, until I leave the machine turned off for a while, after which the same problem occurs again.


I have checked the disk for errors, reset the SMC, and reset NVRAM, but the issue still remains.

The battery maintains its charge and works as expected - it has been replaced recently.

This is a pretty unusual set of symptoms, I have not been able to find any other instances of this discussed online.


Any insights / suggestions as to what this problem could be, or potential solutions would be greatly appreciated.

Answer this question I have this problem too

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You said you recently replaced the battery. Did you use an OEM Apple battery or a cheaper one?

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It was an OEM Apple battery replaced at an authorised Apple store.

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Most machines showing boot problems from this model are affected by the graphic card issue, which may or may not prevent boot, especially when it shows first signs of distress. I’d recommend downloading a benchmarking App such as Valley, from Unigine https://benchmark.unigine.com/valley and try to run it. It will immediately engage the dedicated card and put it to test and if it’s a graphics card issue the screen will get garbled or the Mac will shutdown. This will confirm if it’s a graphics issue and from there we can start other troubleshooting.

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Thank you for your suggestion.

I figured that if the graphics card was the problem, as is frequent among this family of machines, I may as well apply the most recommended fix to see if the issue went away. (https://forums.macrumors.com/threads/for...)

So I booted into recovery mode (cmd + s + r), and executed

nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00

Rebooted back into macOS Sierra, and verified that the AMD card was disabled by plugging in my external display, which, as expected, did not work.

Unfortunately on shutting down the machine and restarting after a while, the problem remains.

This makes me believe it is not the famous graphics card issue, is this a reasonable assumption to make?

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@shyun An 82 pages thread it's too much reading for me to help you answer your question. I've disabled a couple of graphic cards using the more complex and I guess more stable EFI writing method.. I don't know if simply writing a string on NVRAM would achieve the same results, but let me doubt that would suffice. I'd say for testing purposes what I suggested above would be best suited to give you a clear answer about your dedicated card status and condition.

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