Can't install macOS on iMac

Discussion in 'iMac' started by lomontman, Nov 10, 2018.

  1. lomontman macrumors newbie

    Joined:
    Nov 9, 2018
    #1
    I have a iMac retina and was running High Sierra. This morning I installed the latest security update. It installed successfully and the computer rebooted. A short while late I rebooted the computer for another reason and the computer failed to boot successfully. A macOS installation screen came up and I was told that the "Volume contains a mac OS or OS X installation which may be damaged." I restarted the computer into Restore mode and ran Disk Utility. The drive checks out as ok. I tried restoring from a Time Machine backup - it failed. Same message. Tried with 3 different TM backups - all failed. Tried to re-install High Sierra over the Internet - it failed. Tried to install Mojave over the internet - it failed. Got out my USB drive with a week old backup and booted from that drive. The computer boots no problem. Ran Disk Utility on the iMac HD. No problems. I find very little info on the web about this problem, none of it applies specifically to my problem. Any help/ideas would be appreciated.
     
  2. jerwin macrumors 68020

    Joined:
    Jun 13, 2015
    #2
    install a fresh copy of the os & migrate your files from a time machine backup. Directly restoring from time machine can cause problems.
     
  3. CoastalOR macrumors 68020

    CoastalOR

    Joined:
    Jan 19, 2015
    Location:
    Oregon, USA
    #3
    You are not the only person that has had a problem with the Security update on High Sierra:
    https://forums.macrumors.com/thread...update-2018-002-10-13-6-wont-install.2151143/

    Did you try reinstalling the OS from Recovery (command+r)?
     
  4. lomontman thread starter macrumors newbie

    Joined:
    Nov 9, 2018
    #4
    I can't install anything on the iMac at this point.
    --- Post Merged, Nov 10, 2018 ---
    Yes, I tried reinstalling the OS from Recovery - it will not reinstall
    --- Post Merged, Nov 10, 2018 ---
    When a macOS installation fails it asks me to choose a Startup Disk. I choose my old 10.13.6 and it tells me: "You can't change the startup to the selected disk. Running Bless to place boot files failed."

    I'm thinking of just erasing the drive and then trying to reinstall the OS but I'm not sure that's a wise move or not.
     
  5. jerwin macrumors 68020

    Joined:
    Jun 13, 2015
    #5
    Make sure you have a backup-- time machine will work.
    if you hold down option at boot, you can boot up from the time machine disk.

    [​IMG]

    Use Disk Utiity to reformat Macintosh HD: this will erase the disk. Mojave requires APFS.

    Then Reinstall MacOS.

    Then use the Migration Assistant to migrate all your files to your fresh install of MacOS.
     
  6. lomontman, Nov 10, 2018
    Last edited: Nov 10, 2018

    lomontman thread starter macrumors newbie

    Joined:
    Nov 9, 2018
    #6
    I have a TM backup and also a week-old backup to an external drive.
    --- Post Merged, Nov 10, 2018 ---
    Though my Time Machine disk does not show up as a boot option. Looks like I'll need to boot from my external drive to erase the iMac disk.
     
  7. jerwin macrumors 68020

    Joined:
    Jun 13, 2015
    #7
    you don't get something like this at boot? boot screen.jpg

    alexandria is my time machine drive.
    however, if it's a network drive, you'll need to use the "Choose Network" menu
     
  8. lomontman thread starter macrumors newbie

    Joined:
    Nov 9, 2018
    #8
    Looks like I will be back up and running as soon as my files are migrated. Erasing the disk and installing Mojave did the trick. Thanks for all the suggestions. My opinion of Apple has taken a bit of a hit here - wasted a lot of time today trying to fix a problem of their making.
    --- Post Merged, Nov 10, 2018 ---
    The TM drive did not show up. Even when I chose my network the only option available was Macintosh Install or something to that effect. I had to hook up my external USB drive to boot the computer to erase the iMac drive
     
  9. Fishrrman macrumors P6

    Fishrrman

    Joined:
    Feb 20, 2009
    #9
    OP wrote:
    "Though my Time Machine disk does not show up as a boot option. Looks like I'll need to boot from my external drive to erase the iMac disk."

    I'd like to offer a suggestion for the future:
    Download either CarbonCopyCloner or SuperDuper and create at least one "bootable cloned backup" of your internal drive (once it's up-and-running again, of course!).

    If you had a recent bootable cloned backup, getting things back in order would have been a simple process:
    1. Boot from the cloned backup
    2. ERASE the internal drive
    3. RE-CLONE from the cloned backup BACK TO the internal drive
    Things will then be "exactly as they were" at the time the last cloned backup was done.

    OP also wrote:
    "The TM drive did not show up."

    Your experience in this thread is yet one more illustration of why Mac owners should not trust Time Machine. Again and again, it seems to have failed you in "a moment of need".

    Try a cloned backup, as I suggested.
    Both CCC and SD are FREE to try for 30 days.
    If you don't like it, just erase the drive and use it for something else.
     

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8 November 10, 2018