I cannot boot back into OS X from boot camp

If you used any Windows Utilities to modify the partition Map, that is the last time you will see your Mac OS X files again.

Windows is not a pleasant Guest.

Too little details.

How it was installed, whether you pulled all the other drives, if you moved any.

Paragon has some excelent support tools for Boot CAmp and OS X for resixing, install, backup, and drivers.

With Paragon HDM 12 you can clone and make a bootable copy of Windows. Same as you would almost with CCC.

Not sure what Command C buys you if you can but trying to boot from 10.6.3 DVD?

OPTION key shows bootable volumes, x on startup tries to find the first Mac OS X system volume.... resetting nvram will mean you have to reset the default startup disk.

Sure you can pull all the drives except the Mac OS. Windows is funny about where it is, and won't install iwth other drives present that are GUID but then sometimes doesn't show up in Mac OS X startup disk.

I would boot from your emergencvy backup clone of Mac OS or Recovery Moide for Lion and above and repair the drive, and check the health of the drive partition tables (an addition to Lion I assume).

I can't imagine why you would not be able to boot OS X from the Apple EFI boot menu.

Unless, as Grant pointed out, you made some changes to you system using Windows.

I once used Disk Management in Windows Bootcamp to remove drive letters from some partitions on an external HDD(so they wouldn't mount in Windows). As a result, they became inaccessible in OS X.

I have noticed that I cannot boot into OS X Mavericks directly from Windows. Mabye the Bootcamp drivers need to be updated for Mav. But the apple boot menu should work.

Are you the same Todd Edwards that makes Mac Pro upgrade videos for Youtube?

I had the same problem with my mid-2012 MacBook Pro after installing Boot Camp and Windows 7.

It would boot into Windows 7 no problem, but when booting into OS X it would freeze with the beachball of death after showing the grey screen with an Apple logo. It also had no trouble booting off an external FireWire backupve.

After rebooting 5 or 6 times it would eventually load OS X, but after putting the display to sleep the beachball would return and it had to be powered off. It had no trouble booting off an external FireWire backup drive.

There were other strange behaviours too: in Windows, the keyboard backlights would come on for no apparent reason and using the keyboard backlight increase/decrease buttons had no effect.

Running Disk Utility's Verify functions revealed no problems with the drive or the partitions.

I reset the PRAM, but that made no difference.

Eventually a bit of Googling on the symptoms lead me to the support page for resetting the Intel System Management Controller:

http://support.apple.com/kb/HT3964

After following those instructions, everything is back to normal. An unexpected but pleasant side-effect is that applications now launch more quickly in OS X.

I'm assuming that something on the Windows side fiddled with the SMC and caused these problems.

I got the same issue.

Grey Apple with spinning progress that on and on for hours (if I let it).

I took out the HDD and access the data from somewhere else.. no problem.

Then I put the HDD back and tried to reinstall the MacOS.. no can't do. Installer refuse to do its job, making excuses like cannot write and error and stuff like that. Heck I can't even format the drive from the disk-utility that comes with the installer.

So then I put that same HDD to an external USB and managed to install just fine. Wow.

The installation process went on to a ready-to-use state. Running (and booting) off a USB external enclosure.

So I put the HDD back inside the laptop (MacBookPro) and.. it got stuck again.

Thinking it was the PRAM, I hold Cmd + Alt + P + R to reset the PRAM.. reset was successful, my problem is still there. So it wasnt the PRAM.

I guess the question is:

Could this be because of the hardware? (say HDD controller on the logic board)

Or is there any other things I need to reset (EFI? or something else?)

fact:

HDD is fine.

Files are fine.

HDD able to be installed and booted well from off the laptop.

HDD unable to be booted nor installed if its INSIDE the laptop.

I have a similar problem with 2010 Mac Pro. After running Windows 7 SSD for several months, I selected Mac OS using the Windows Control Panel. The Mac hard drive was Mavericks 10.9.1. After a protracted black screen it finally appeared to boot, and reached the Mavericks desktop. There was no cursor available, and the Menu Bar was dimmed. Only option was to turn off with the power switch. Next I tried employ the OPTION key on startup to access the boot manager, results was black screen, never had any bootable drives appear. No Windows 7 and not the formerly fully operational MAC OS hard drive. Also tried another Mac keyboard, using OPTION key on boot...no change: no boot drives ever appear. I can pull the drive sled out of this Mac Pro and insert into another 2010 Mac Pro, works normally. All utilities showed drive fully operational and normal. Finally repartitioned, and formatted the hard drive with Disk Utility, and reinstalled Mavericks 10.9.5., while installed in the second Mac Pro. Pulled the drive sled and put in original Mac Pro, same problem; it appears to boot to Mac desktop, menu bar dimmed, no cursor. Cannot access the Mac OS drive by any normal means. The SSD was originally partitioned and formatted in Mac Disk Utility, then Mavericks 10.9.1 installed. My friend who owns the Mac Pro with this problem is a former Windows user who crossed over to Mac but never totally was comfortable, and eventually went back to Windows 7 (on the Mac Pro) exclusivley. Even if you pull all drives and attempt to boot into Mac OS, the result is always the same, desktop is reached, menu bar dimmed, and no cursor. SMC reset and NVRAM reset have no obvious effect. Also replaced battery on main board, with no change noted. What could make the menu bar appear grayed out and the cursor disappear? It appears by friend has a 8 core Mac Pro that runs only as an Windows machine.