Installed Windows now OSX GONE! HELP

Discussion in 'macOS' started by davidb8, Sep 11, 2015.

  1. davidb8 macrumors regular

    Joined:
    Sep 30, 2013
    #1
    ok I installed windows 10 using boot camp. followed the instructions as I have done a few times in the past with no problems.

    but now I cant reboot into OSX. the partition is still there... I can see it in disk management on windows but can not boot to OSX. It even shows OSX in the boot camp software on windows but when I select it and restart, it comes back to windows.

    holding option key does nothing. pressing X or C or any of the other things iv read online have worked. reset NVRAM too and still only windows.

    How do i fix the booting? the partition is still there but no boot. preferably DONT want to reinstall OSX.
     
  2. davidb8 thread starter macrumors regular

    Joined:
    Sep 30, 2013
    #2
    ok.. just booted into internet recovery. hit the apple logo and selected startup disk. The OSX partition was there but I had to unlock it with my password to enable it. then restarted and it still comes straight into windows!
     
  3. blackboxxx, Sep 11, 2015
    Last edited: Sep 11, 2015

    blackboxxx macrumors regular

    Joined:
    Sep 10, 2008
    #3
    Based on your description it appears that you have FileVault enabled. Therefore the fact that you can't select your main OS X partition by holding option or X key is completely expected — it's encrypted, after all, and the EFI firmware does not know anything about FileVault.
    The normal boot sequence with FileVault enabled is like this: EFI -> Recovery HD -> OS X.
    In your case, something on your recovery partition got corrupted, that's why you can't boot.

    WARNING: since your drive is encrypted, make sure that you have current backups of your data before doing anything. Especially steer clear from Disk Management in Windows, I have seen it change the partition type on several HFS+ disks just by opening it.

    Also, booting internet recovery can be very time consuming depending on your internet connection. If you have a Time Machine backup, you can boot into recovery from it by holding down the option key at boot. If not, I recommend you boot into internet recovery and install OS X on a spare USB drive (can be external hard drive or a flash USB stick ≥8 GB). It won't affect your internal drive and will make the recovery process much easier.

    I can think of 3 possible scenarios (from easiest to repair to most difficult):
    1. Windows Disk Management, as it is wont to do, changed the partition type of your Recovery HD from Apple_Boot to Apple_HFS.
      • Difficulty: easy
      • How to detect:
        • boot into recovery mode, open Terminal and type this command:
        • Code:
          diskutil list disk0
        • look for the partition type of Recovery HD (disk0s3): if it is anything except Apple_Boot, then you have this problem.
      • How to fix:
        • while still in Terminal in recovery mode, type this command:
        • Code:
          asr adjust --target /dev/disk0s3 --settype Apple_Boot
    2. Boot caches on recovery partition got corrupted
      • Difficulty: easy
      • How to detect:
        • If the partition type of Recovery HD, as determined in case 1 above, is already Apple_Boot, but the system refuses to boot into OS X normally, you probably have this problem
      • How to fix:
        • open Disk Utility in recovery mode, then unlock and mount your internal drive
        • quit Disk Utility, open Terminal and type this command (assuming your main partition is called "Macintosh HD"):
        • Code:
          kextcache -u /Volumes/Macintosh\ HD
    3. Recovery partition is damaged or missing completely
      • Difficulty: difficult and time consuming (several hours)
      • How to detect:
        • If the solution in case 2 above doesn't work,
        • or there's no Recovery HD on disk0 at all, then you probably have this problem
      • How to fix:
        • The most reliable method is probably to backup most important data and reinstall OS X.
        • The more involved and error-prone method is to download OS X installer from Mac App Store and then use the dmtest command from "Recovery HD Update" package to recreate Recovery HD partition.

    In my experience with Windows 10, I had a similar problem — Disk Management silently changed the partition type of Recovery HD. It was very easy to fix (see case 1 above), however my drive was not encrypted. In your case, FileVault complicates things because if something goes wrong, there's a risk to lose all your data.
     
  4. davidb8 thread starter macrumors regular

    Joined:
    Sep 30, 2013
  5. davidb8 thread starter macrumors regular

    Joined:
    Sep 30, 2013
    #5
    Ok. Tried the first 2 options and neither of them worked.

    It says Apple_Boot is disk0s3.

    I can't even access the partition from Windows using transmac.

    I might have to use terminal to copy important files and then just wipe and start fresh
     
  6. patternjake macrumors member

    patternjake

    Joined:
    Sep 17, 2015
    #6
    I know I'm being daft but won't holding the ALT key while the Mac chime plays and holding it down bring up the boot manager?
     
  7. davidb8 thread starter macrumors regular

    Joined:
    Sep 30, 2013
    #7
    Yes it does bring up the boot manager. With only Windows as an option
     
  8. patternjake macrumors member

    patternjake

    Joined:
    Sep 17, 2015
    #8
    You are going to have to do a complete format and re-install of OS X unfortunately.
     

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