Please Help! Cannot reinstall Sierra on iMac 2011

Discussion in 'iMac' started by gk32, May 17, 2017.

  1. gk32 macrumors newbie

    Joined:
    May 17, 2017
    #1
    Help please! I have iMac 2011, get it last year from craigslist with El Capitan on that moment. Upgraded to Sierra recently. Then decided to erase disk and reinstall. But now I cannot because it shows that disk is locked.

    Here are details.


    1. I restarted iMac

    2. No keys need to be pressed/hold - it goes directly to macOS Utilities with a 4 options: Restore from Time Machine Backup (I don't have backup), Reinstall macOS, Get Help Online, Disk Utility

    3. I select Reinstall macOS, then Continue

    4. Opens window macOS Sierra, where I click Continue

    5. After clicking Agree with license agreement it goes to next window

    6. Here under macOS Sierra I see label "Select the disk where you want to install macOS" and 2 disk icons: OS X Base System (499 GB) and Recovery
    HD (650 MB). BTW, sometimes after restarting second disk Recovery HD doesn't appear here[​IMG]
    7. When click on OS X Base System disk icon, it shows warning :"This disk is locked."
    upload_2017-5-17_21-21-10.png

    8. If click on next icon with Recovery HD, it just shows what arrow with no label

    9. Anyway, Install -> button never gets enabled

    10. The only way too get out of this installation screen is to restart iMac

    11. After restarting and getting macOS Utilities, I go to Disk Utility

    12. Screen shows one Internal disk: ST3.....Media, when expand, shows disk icon OS X Base System
    upload_2017-5-17_21-21-57.png
    13. If OS X Base System is selected, only first tab "First Aid" is enabled on Disk Utility, rest - Partition, Erase, Restore Unmount - are disabled. If running first aid, no errors shown up

    14. If disk ST3..... Media is selected, it enables also second tab Partition

    15 . From here you cannot click add(+) because it's disabled.. upload_2017-5-17_21-22-14.png

    Any help will be gratefully appreciated
     
  2. tdhurst macrumors 68040

    tdhurst

    Joined:
    Dec 27, 2003
    Location:
    Phoenix, AZ
    #2
    Looks like you're starting up with the hard drive you want to reinstall the OS on.

    I believe you'll need to start up from the recovery or network drive, here's the key combos to hold during startup: https://support.apple.com/en-us/HT201255
     
  3. Fishrrman macrumors G4

    Joined:
    Feb 20, 2009
    #3
    Get a USB flash drive, 16gb or larger.

    Create a bootable installer on the flash drive using either:
    1. Install disk creator
    or
    2. Diskmaker X
    or
    3. The terminal

    Boot from the installer flash drive.

    Re-initialize the internal drive (so you start "from scratch")

    Install onto the re-initialized drive.
     

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