MacBook Pro boots into grey screen

Install gfxCardStatus (https://gfx.io) and set it to "i" (integrated graphics only). It will allow your MBP to run on integrated graphics only, bypassing the discrete GPU which has the issues. This may allow your MBP to run normally, although it will have reduced graphics performance when permforming demanding graphics tasks. The alternative is replacing the logic board, which is not cost effective on a machine that old, unless gfx does not resolve the issue and you really want to keep this MBP.

There is an acknowledged bug in the current version of Cody Kreiger's Open-Source gfxcardstatus, and the developer has confessed he does not have time to fix it right now.

There is a fork off the main build by steveschow available that seems to fix that problem for current versions of MacOS such as ElCapitan and Sierra. He provides a finished .app for direct download -- you do not have to compile anything.

https://github.com/steveschow/gfxCardStatus/releases

Also note that if your Mac does not run long enough to allow gfxcardstatus to be added, this is not really practical.

In addition, Steve Schow writes that he has abandoned further development -- because there are better solutions available [for both the 2010 model and 2011 models]. In particular, the use of ArchLinux bootable CD to gain access to and re-write the EFI on the drive, and permanently disable the discrete graphics chip. This page and scroll down past the list to the blog:

http://github.com/steveschow/gfxCardStatus

There are two similar procedure listed. I used the second from MacRumors as it seemed easier. I have made the Arch Linux bootable CD on another Mac, and tried this approach. I now have a perfectly-functioning MacBook Pro late 2011 15-in model with Discrete Graphics disabled. Runs just fine. But NO external display support any more.

I have discontinued use of gfxCardStatus to solve the MBP kernel panic problem as the issue is better solved on 2010 models with the nVidia GPU by the following hack:

https://github.com/julian-poidevin/MBPMid2010_GPUFix.

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I did not suggest you replace any logic boards. I suggested you install a free Utility and get control of your computer again.

Download the Utility on another computer and copy it to a USB thumb drive.

I can boot into single user mode and move around the drive and see my files.

use single-User mode to copy the file off the thumb drive into the /Applications folder.

restart your Mac, and use gfxcardstatus to disable the discrete GPU.

It is very likely that your Macbook pro graphic card chip has failed, you have to take your Mac to technical service , they would diagnose the problem and maybe they can fix it either by replacing the chip or by replacing the mother board. Another possible fix is to reflowing the chip in order to melt the solder but I don t recommend this fix because it can fail again.