Hello folks, I already posted this on Ask Different but didn't get any good answer yet. It may be too specialized for Ask Different, but I was told I may found kext experts here 1 - Original issue I own a Macbook Pro 15" from Early 2011, which suffers from the well-known-but-denied-by-Apple GPU problem. TL;DR: the AMD Radeon HD 6XX0M is dead and the Macbook can't boot, or can boot but with huge graphic glitches on screen. 2 - Workaround There is a workaround to this problem, which consists to disable the AMD GPU and only use the Intel HD 3000 chipset. The main way to do this is to use a software like gfxCardStatus. However, since my Macbook wasn't booting (stuck on blue screen after Apple logo), I managed to disable my AMD Radeon HD 6490M by entering single-user mode and deleting the following files from /System/Library/Extensions/ : AMDRadeonAccelerator.kext AMDRadeonVADriver.bundle AMDRadeonX3000GLDriver.bundle AMDRadeonX4000GLDriver.bundle ATI2400Controller.kext ATI2600Controller.kext ATI3800Controller.kext ATI4600Controller.kext ATI4800Controller.kext ATI5000Controller.kext ATI6000Controller.kext ATI7000Controller.kext ATIFramebuffer.kext ATIRadeonX2000.kext ATIRadeonX2000GA.plugin ATIRadeonX2000GLDriver.bundle ATIRadeonX2000VADriver.bundle ATISupport.kext 3 - Remaining problems But, as I said, this is just a workaround to get OS X to boot. I now have 2 main issues: - I can't plug an external screen on the Thunderbolt port - I can't play any avi or mkv video I know there isn't any solution for the first issue, since the Intel HD 3000 is not even physically linked to the Thunderbolt port. However, I am looking for a solution to the second issue. The Intel HD 3000 chipset may not be a killer GPU, but I am sure it can handle a simple video, and even 1080p videos. When I open a video file in VLC, I get the following error: And in the logs: I think Mac OS X is trying to get OpenGL acceleration thanks to the AMD GPU. And since the GPU is supposed to work properly, it never tries to get the adequate features from the Intel HD 3000 chipset. So, is there any way to get more from this chipset?