In case this helps someone, I just wanted to share a fix to an issue I encountered that prevented me from booting into Windows 8 on a MacBook Pro (2012) running Mountain Lion and Boot Camp.
I had attempted to reboot into Windows 8, only to find that Windows would never finish booting, forever hanging at the startup screen with the Windows logo and and spinning circle of dots. Nothing seemed to work, and the Automatic Recovery tools were also on the other side of the spinning circle, unable to finish loading.
I ran into a fix for this issue that falls into the “one weird trick” category, using a feature of VMWare Fusion. I tested this with the standard version of VMWare Fusion 5, but there is a free trial of VMWare Fusion 6 available that should work as well.
In short, I followed this guide to boot the existing Boot Camp partition as a Virtual Machine.
After a short automated setup process, the virtual Windows 8 was able to start booting, and continued on beyond the spot where it would typically hang. The startup process complained about being unable to finish booting last time (and many times before that…) and offered up the Automatic Repair options (which I skipped).
After skipping the automatic repair, it was possible to get into the Advanced Startup Options and boot into Safe Mode.
Rebooting out of Safe Mode, the virtual Windows 8 install was able to start normally, without any issues!
As a last step, I rebooted the entire system, crossed my fingers, and Windows 8 made it past the spot that it was previously getting hung up on, and booted normally. Crisis averted, no data loss.
I’m hoping that this process won’t trigger Windows re-activation. It hasn’t so far, and I’ll add an update if that turns out to be a problem.