Solved: Booted to Single-User mode and disabled Radeon GPU.
Details of investigation:
Initially I suspected hard-drive corruption and went about trying to remedy that. Unsuccessfully, I tried the following, with each continuing to hang as described above:
- Safe boot
- Boot into recovery (including Internet Recovery)
- Boot from install media on USB drive
- Boot from OS X installation on USB drive
- Clear NVRAM
- Reset SMC
I also ran the Apple Hardware Test many times without it finding any issues.
Verbose safe boot (Cmd+Shift+V) output everything that I'd expect to see but would then hang as described above.
After coming across more posts online of GPU related problems I revisited this as the cause:
Attempting to boot Ubuntu from a USB flash drive, I could only get as far as Grub. When trying to boot Ubuntu Desktop or run the graphicstest in Grub the system would hang.
At this point, running Apple Hardware Test hung right before the end of the standard test, possibly [guessing] when doing a video test.
Based on the advice in the Apple Discussions posts above I did the following:
- Boot into Single-User mode
- Execute the following commands:
/sbin/fsck -fy /
/sbin/mount -uw /
mkdir /Disabled_System_Library_Extensions
cd /Disabled_System_Library_Extensions
mv /System/Library/Extensions/ATI* .
mv /System/Library/Extensions/AMD* .
touch /System/Library/Extensions
exit
This time the machine booted all the way through. However, graphics are extremely slow, even just transitions when minimizing windows. I will be taking my MBP to Apple to demand a replacement as the large number of reports of others facing similar issues makes it look like a recurrence of a similar GPU-related failure that resulted in them doing a recall.
What is the year and model of your MacBook Pro? There is a known graphics failure in the 2011 models of MacBook Pros that is now leading to a class-action lawsuit .
I would also try resetting just the SMC by pressing Shift+Control+Option+Power button at the same time while the computer is off and plugged into power. (You only reset the PRAM according to the steps you have done above.)
Best Answer
Try resetting the SMC and resetting the PRAM.
It's also possible that your hard drive is failing in such a way that the computer can't boot. I haven't seen that often but it can happen (if you hear weird clicking sounds on boot, that increases the likelihood of this being the case).
It's pretty easy to take the hard drive out of your computer (all you need is a a phillips-head #00), it may be worth removing the hard drive, then trying to boot to an external disk.
MacBook Pro take-apart guides.