iMac won't start up

Discussion in 'iMac' started by cliffy1, Sep 14, 2016.

  1. cliffy1 macrumors newbie

    cliffy1

    Joined:
    Sep 14, 2016
    #1
    How do I start a iMac that keeps shutting down half way through start up?
     
  2. cliffy1 thread starter macrumors newbie

    cliffy1

    Joined:
    Sep 14, 2016
    #3
    The apple symbol comes up and the slider window starts to move acros. It gets about 1/4 of the way and the machine shuts down.
     
  3. grahamperrin macrumors 601

    grahamperrin

    Joined:
    Jun 8, 2007
    #4
    OK. Now boot in verbose mode and take a note, or a photograph, of the last thing that is on screen before the unexpected shut down.
     
  4. cliffy1 thread starter macrumors newbie

    cliffy1

    Joined:
    Sep 14, 2016
    #5
    I ran Disk repair. It said the disk cannot be repaired. I think it might be toast.
     
  5. grahamperrin macrumors 601

    grahamperrin

    Joined:
    Jun 8, 2007
    #6
    OK. Now the shutdown may be explained.

    There is a limit to the number of times that the operating system will automatically run fsck_hfs when an HFS Plus startup volume is found to be DIRTY.

    When that limit is reached, no further attempt will be made to repair the file system inconsistency (until the next boot/startup) so to me, it makes sense to automatically shut down.

    If you are extremely lucky, further attempts will successfully repair the inconsistencies. Alternatively, further attempts may worsen the situation.

    Recommended reading: Unable to install Sierra GM
     
  6. cliffy1 thread starter macrumors newbie

    cliffy1

    Joined:
    Sep 14, 2016
    #7
    I took a picture of my screen after starting with Command-option-R, if this helps:
     

    Attached Files:

  7. Fishrrman macrumors G5

    Fishrrman

    Joined:
    Feb 20, 2009
    #8
    You need to try booting from an "external source".

    Otherwise, you're going to keep going around in circles...
     
  8. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #9
    You answered your question by saying the drive is toast. No amount of debugging, will help you. Unfortunately the drive seems to have failed.

    If its in warranty, call apple, if you feel brave open it up yourself, but its not for the faint of heart. Its a risky proposition especially if you have a fairly new iMac. If not, then call an authorized repair shop (or apple) to get it repaired
     
  9. grahamperrin macrumors 601

    grahamperrin

    Joined:
    Jun 8, 2007
    #10
    Yes and no, because it shows the automated HFS Plus file system check (fsck_hfs) only part way through its routine, checking catalog file … without showing the point at which a problem occurs.

    Hint: if that's a row of rrr… in your photograph, then you can safely release the R key :)

    More importantly, if you want Recovery OS then it's Command-R (not Option-Command-R).

    Back to my first link in post 2 above, try Apple Diagnostics. Do the results of a diagnostic routine mention anything about the disk?

    Anything about 'S.M.A.R.T.' or 'SMART' maybe?

    (You might, alternatively, get S.M.A.R.T. information for the disk (that contains the file system) with Disk Utility in Recovery OS, but I should take this opportunity to run Apple Diagnostics.)
     

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