I've got a march 2010 MBP, Windows 8 installed on a bootcamp partition, PD9 uses this partition. I try to upgrade to 8.1 via the Windows app store. Upon restart it gives me a boot error screen of some sort, saying: Recovery Your PC needs to be repaired A required device isn't connected or can't be accessed Error code: 0xc000000e , giving me options to press enter try again, press f8 for Startup Settings, or press f9 to use a different operating system. The only option that works is f9, which loads up my existing Windows 8 installation, but then an error screen comes up saying "Couldn't update to Windows 8.1". It's as if the installer is targeting the OSX partition. I also happen to get the same course of errors when trying to install via win 8 running natively. It looks as though some people in the same scenario (using win 8 on bootcamp) have passed this obstacle and are on to others. Any tips?