MacBook Pro Black Screen After Windows 7 Crash

A few days ago, when I was working on my MacBook Pro (late 2012 model), all of the sudden Windows 7 crashed, and the display got jumbled. It appeared that something went wrong with the video adapter. So, after waiting for 4-5 minutes (and no response), I forced shutdown the machine by pressing the shutdown button for 8-10 seconds.

After few seconds, I pressed the Power button again. The usual boot gray screen appeared, with boot chime sound, and then screen turned to black. It appeared that processor was working (from the fan speed noise), but there was no display. Note that my MacBook Pro, by default boots to Windows 7. I tried this 2-3 times with same results. In panic, I finally tried to launch the OS-X, it stared the boot process, but then got stuck again near the end, and kept showing the gray screen.

Searching the web, I found the following article related to my issue:
Mac OS X: Gray screen appears during startup

The steps in this article fixed my issue, but in a bit different order. To fix the issue, I first have to reset the NVRAM. Here is very good article on how you can do this (check “Resetting NVRAM / PRAM” section):
About NVRAM and PRAM

Once that’s done, the boot process continued one step further, but this time it got stuck on the blue screen (displayed right before the Finder login window). To fix this issue, I re-booted OS-X in Safe-Mode (by pressing down Shift down during start-up), and it finally fixed OS-X booting issue. Now OS-X was booting and loading fine. A big relief there.

However, I was still getting the black screen when loading the Windows. The bad new was that it was not even booting from the Windows boot disk i.e. still black screen with no display. I tried resetting thePRAM, SMC, but no luck.

My hunch was that during crash something went wrong with video adapter. And this was probably not some hardware issue, but some invalid configuration got stored in the video memory. This is because, if I run the Window and get a black screen, my next OS-X load was failing as well, and then I have to reset the NVRAM, and then run again in safe mode.

I noticed, one interesting pattern though, and that’s when the Windows booting fail with black screen, and I run the OS-x again in safe mode. If I then I run my Windows in VirtualBox on OS-X, then next Window boot (bootcamp) will work correctly. However, I was having that stuck and crash issue frequently on OS-X anyway. After few testing and tries, I found that problem is happening due to “Automatic Graphics Switching” option of OS-X. Apparently, when trying to do the graphics switching, it sometime was crashing. And if it crashed while the Intel graphics card is current one, next Window boot will show black screen.

I then searched the web, and found it to be known issue with few 15″ MacBook Pro models. Fortunately, there were already firmware updates available, so I updated my Snow Leopard to latest 10.6.8 version, and then applied all available software and firmware updates. There was also one update available for SMC firmware, which I think was key in resolving my the crash and stuck issue on OS-X.

However, in all this recovery and testing process, somehow my Windows partitions got lost. The weird thing was these paritions were accessible in OS-X, but when I boot from a Windows disk, these partitions were not being recognized. On checking the file type of these partitions using disk utility software, I found that these have been converted to “RAW” format. Again, I was lucky that there is already very a nice and freeware application available which helped me restored this:
http://www.cgsecurity.org/wiki/TestDisk

There is very good step by step guide on how to use this utility:
http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step

With Windows partition restored, everything is back and fully working again. I have to spend around 2-3 days in all this, but good thing is that all the things are restored, without any data loss.

Tags: Black Screen, Boot, MacBook Pro

This entry was posted on Monday, August 26th, 2013 at 1:30 am and is filed under OS X, Windows. You can follow any responses to this entry through the RSS 2.0 feed.
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