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I have a Bootcamp partition with Windows 8.1 that I rarely use. Last night I was in OSX, closed the lid, and when I opened it this morning it was in Windows and I cannot get out.

  • Booting with the option key down does nothing (still boots straight to Windows)
  • Going to Advanced Boot Options in Windows shows Mac OS X as an alternative boot device, but when I choose it and reboot, it still goes into Windows.
  • I've read that holding X on boot forces to OS X - never heard of that before, but also tried it with the same results as above.

I've reached the end of what I know how to do - other troubleshooting paths to take?

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The Mac hardware stores the boot volume in NVRAM so you could power off the computer and then reset things by holding the Command Option P R keys down.

Once you've heard two boot chimes you can release things and if the Mac OS X volume is viable it will boot first. If that doesn't work then it's likely that the OS X volume has issues and the system is failing to boot there and falling back to the second viable OS - Windows.

You might be able to see that in the console if you boot verbose or single user mode.

The official fix at that point would be to boot into Recovery and then see about repairing or reinstalling OS X.

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    If it's a failing OS X volume then I would recommend backing up as much as you can fast before reinstalling OS X. – MichaelStoner Aug 19 '14 at 15:14
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    That worked, thanks! OSX came straight back up exactly as I'd left it. For my own understanding, can you explain a little more how this might've potentially happened, and what booting with opt cmd P R does that got around what the normal boot mode couldn't do on it's own? – Rex M Aug 19 '14 at 15:42
  • If the code is supposed to write 1 to boot to mac and 2 for windows - perhaps it adds one or subtracts one to change things. If the value stored in NVRAM was 1.3 then the algorithm can't recover. It's clearly not that simple, but corruption can and does happen and starting from the defaults often is a good recovery option. I'm glad it was the obvious / simple failure and not something you needed to reinstall. – bmike Aug 19 '14 at 16:40
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If this helps anyone else:

The SMC, PRAM, VRAM, etc. combinations didnt work for me (Opt key still wouldnt work), however worked for me today was recovery mode: https://support.apple.com/en-us/HT201314

I ran First Aid and then selected the desired startup disk and that seemed to boot my Mac back up.

I would also avoid using external/bluetooth keyboards, etc. in this situation.

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