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Upgrade Failure

Was in the middle of this OS upgrade and lost power and internet connection. Now machine is stuck and won't boot up. Tried powering down and starting up again, but not working. How do I stop the update or restart from beginning?

Posted on Dec 18, 2020 8:51 AM

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Question marked as Apple recommended

Try holding the Option key just after the startup chime (or powering on the Mac if it is newer and doesn't chime). See if there is an "Installer" option which may let the installer continue or if there is a "Macintosh HD" option try it to boot normally.


You don't mention what version of macOS was previously installed or which version you are installing. You can try booting into Recovery Mode to begin reinstalling macOS again (either with the original OS or the one you were trying to install -- which one you get may depend on how far the progress got).


If you have another compatible Mac you can also try creating a bootable macOS USB installer:

https://support.apple.com/en-us/HT201372

Posted on Dec 19, 2020 1:56 PM

1 reply
Question marked as Apple recommended

Dec 19, 2020 1:56 PM in response to RobertGJ

Try holding the Option key just after the startup chime (or powering on the Mac if it is newer and doesn't chime). See if there is an "Installer" option which may let the installer continue or if there is a "Macintosh HD" option try it to boot normally.


You don't mention what version of macOS was previously installed or which version you are installing. You can try booting into Recovery Mode to begin reinstalling macOS again (either with the original OS or the one you were trying to install -- which one you get may depend on how far the progress got).


If you have another compatible Mac you can also try creating a bootable macOS USB installer:

https://support.apple.com/en-us/HT201372

Upgrade Failure

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