Geetarman64

Q: iMac won't boot after Sierra update...

Not sure what to do. Just did the Sierra update and now my system freezes during boot and powers down.

 

Anyone else seen this? Any idea what I can do?

iMac

Posted on Oct 6, 2016 5:20 PM

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Q: iMac won't boot after Sierra update...

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  • Helpful answers

  • by Rysz,Helpful

    Rysz Rysz Oct 6, 2016 11:51 PM in response to Geetarman64
    Level 7 (20,988 points)
    iPad
    Oct 6, 2016 11:51 PM in response to Geetarman64

    Try a Safe Boot. Otherwise, you might to reinstall macOS.

    ----------

    Shut down your Mac. Use the power button if you need to. Now start it with the Shift key held down. This will start it into Safe Mode, with all extensions turned off. Safe Mode is slow to start, so give it time, it's checking a bunch of tasks. If it works OK in Safe Mode, restart normally. If it works now, you're done.

     

    If the problem returns after restart, you might have an extension conflict. Turn off all extensions via System Preferences. To isolate which extension is at fault, turn on one extension at a time, restarting in between, until you find the bad one.

  • by Geetarman64,

    Geetarman64 Geetarman64 Oct 6, 2016 11:53 PM in response to Rysz
    Level 1 (8 points)
    Desktops
    Oct 6, 2016 11:53 PM in response to Rysz

    Ended up using Diskwarrior. Got the mac to boot. However Sierra had not installed. Tried to update agsin and install failed. Thanks for the help.

  • by K Shaffer,

    K Shaffer K Shaffer Oct 7, 2016 12:14 AM in response to Geetarman64
    Level 6 (14,513 points)
    Desktops
    Oct 7, 2016 12:14 AM in response to Geetarman64

    Did you try to use the Disk Utility available through the OS X Recovery startup, and attempt to repair the hard drive

    in the computer? There may be an issue whereby the drive could have defects, if so, it would need replacement.

     

    • About macOS Recovery - Apple Support

     

    A third-party or non-approved replacement hard drive version may not have the sensor; as such the cooling fan

    could run full and have no upper limit. The sensor sets the limit. Depending on the model iMac, opening the unit

    to replace or inspect inside may be troublesome. A few are easier for DIY part replacement than others. The

    iFixit repair guides for Mac can be helpful pre-view the level of difficulty and steps involved, if repair is needed.

     

    • iMac Intel repair guides - iFixit:

    https://www.ifixit.com/Device/iMac_Intel

     

     

    A visit to an Apple store with Genius with appointment set ahead to assure

    you of a time reservation, may help to check for causes of the actual problem.

     

    Good luck & happy computing!