I'm stuck to find the reason my iMac is sometimes entering in Hibernate (or standby) mode.

Here is my configuration:

  • OSX version: macOS Mojave (but I have this issue with the previous versions too),
  • Model ID: iMac 14.3,
  • Intel Core i5 2,9 GHz
  • Boot ROM version:
  • SMC version: 2.17f7

Note: I have an iMac, not a Mac book, so there no battery.

Symptoms: sometimes (once a week or every two weeks), the computer enter in hibernate mode: the screen shut down and, after around 15 seconds, the cooling fan is stopping. Once the cooling fan is stopped I can wake the computer up: the session window is displayed… I can the login and continue to work. But, often, I can only work 15 seconds and the computer enter in hibernate mode again. The 15 seconds seams to be a constant.

Sometimes, when I choose "suspend activity" in the Apple menu, and wait for a while, the problem is temporary solved. Rebooting the computer doesn't solve the problem. I also tried to unplug it without success.


↪ pmset -g
System-wide power settings:
Currently in use:
 standby              1
 Sleep On Power Button 1
 womp                 1
 halfdim              1
 hibernatefile        /var/vm/sleepimage
 powernap             1
 autorestart          0
 networkoversleep     0
 disksleep            0
 standbydelayhigh     86400
 sleep                30 (sleep prevented by AddressBookSourceSync, sharingd)
 autopoweroffdelay    28800
 hibernatemode        0
 autopoweroff         1
 ttyskeepawake        1
 displaysleep         30
 highstandbythreshold 50
 standbydelaylow      86400

I really appreciate some help to solve this recurring issue.

more info:

  • Time Machine was enabled (I just turn it off to see).

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