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unexpected shutdown

How do I know if my iMac's apparently random shutdowns are to do with software or hardware? I've made a Text Edit file of the report - can I post it here as copy/paste or is there a way to attach the file?

With thanks.


(It says High Sierra below but should be Catalina 10.15.7.)

Posted on Dec 26, 2020 8:59 PM

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Question marked as Top-ranking reply

Posted on Dec 27, 2020 1:58 PM

You can use the additional text option:



.. to post large amounts of text :-)

8 replies

Dec 27, 2020 2:12 PM in response to Gillylal Fordham-Lear

That's a kernel panic; could be either software or hardware.


Unplug all non-essential devices (e.g. printers that you don't need to use for an hour or so) - if the problem doesn't reoccur, you might have a problem with one of those devices.


Reboot into recovery mode (holding down Command-R on startup) then use Disk Utility to run First Aid on the internal drive to see if you have any software corruption.

Dec 28, 2020 12:42 AM in response to The_Knowledge_Seeker

Thank you. I didn't give a full enough background in my 1st post. The shutdowns have happened maybe half a dozen times over the last 3-4 months. After the 3rd or 4th time, I booted into Recovery mode and did 1st aid on the internal drive - no problems reported but quite a while elapsed before next shutdown, and then another after a couple of weeks.


I found this page which outlined what to do if software or hardware - hence my original post.


I'm going through my Applications folder & deleting old 3rd party software. Hesitant about disconnecting 2 external hard drives (did 1st aid on these while in R mode - no issues reported) because one is ™ and the other for daily internal drive backups with Carbon Copy Cloner. Only other peripheral is quite old Brother laser printer and am keeping that disconnected except for occasional use.


If I get another shutdown with a different report from the one just posted, I'll be glad of your help again.



unexpected shutdown

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