2015 IMacs shut off randomly & automatically multiple times a day...

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Level 1

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2015 IMacs shut off randomly & automatically multiple times a day...

I have a number of 2016 IMacs for our department just recently upgraded to High Sierra. Now they shut off automatically & randomly, and will sometimes not turn on.

After reading through the forums I tried removing the power cord for at least 15 seconds and trying to power on again. They will work for a while (30 minutes or so) and then shut off again.

Could it be the power supply failing? The IMacs are plugged in to surge protectors. We have six that are doing this, all after the upgrade.

Imac Late 2015

OS 10.13.3

3.2 GHz Intel Core i5

8GB 1867 MHz DDR3

iMac with Retina 5K display, macOS High Sierra (10.13.3)

Posted on Mar 5, 2018 8:48 AM

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Answer 1

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woodmeister50

Level 6

19,675 points

Mar 5, 2018 9:22 AM in response to photosjsu

Use one of the iMacs and boot into the RecoveryHD

(About macOS Recovery - Apple Support)

While there, run Disk First Aid on the main boot volume. hen

complete, if there are errors do the repair. When it is done

or there are no issues found, just let the iMac sit and see if it shuts

down on its own while in recovery mode.

If it doesn't seem to shut down, then there probably is not a fundemental

hardware issue. Then reboot into safe mode (hold down the shift key when

rebooting). It will take a bit longer than normal but once done, see if it does the

shut down as well.

The first step, determines if there is some base hardware issue.

The second will stress the system a bit more, however only Apple

drivers will be loaded and no 3rd party drivers. This may determine if

there is some 3rd party driver issue causing a problem.

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2015 IMacs shut off randomly & automatically multiple times a day...

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