I have a problem on my iMac (late 2013) ever since I installed High Sierra (10.13 - 17A405). When my iMac goes into sleep mode because I'm away for too long, or when I manually activate sleep mode (with holding the power button for a few seconds), it always restarts because of an encountered problem.

This gets really frustrating since this is my iMac at my work place and it happens multiple times a day. For my work I have a few programs and browser tabs open and it gets really annoying having to "ready" my computer before I can get work done multiple times a day.

For a temporary "solution" I keep my iMac inactive period (before it goes to sleep) really high (on 2 hours or so), so that whenever I leave my work space for appointments it is still on when I come back. But that is no solution and I still get this problem a few times a day

How can I prevent these reboot? I already tried resetting the PRAM, but don't know what to do other than that.

  • Try this in Safe Mode or with a different user account. Set your sleep mode to go into effect sooner so you don't have to wait and see if the problem goes away.
    – Allan
    Oct 16, 2017 at 9:13
  • I know the problem doesn't go away, because I still have it a couple times a day. What do you want me to do in Safe Mode? I will try the different user account, thanks for the tip!
    – ZoFem
    Oct 17, 2017 at 5:50
  • Operate as you normally would, but in Safe Mode. Set the sleep timeout for a short duration so you "force" the issue sooner - this is for testing.
    – Allan
    Oct 17, 2017 at 10:43
  • I tried in safe mode, I also set sleep time to 1 minute. It worked a couple of times when I was only a few minutes away (toilet/coffee break). But when I went away for a longer period of time (around 30 minutes) and came back it still had restarted and I was out of the safe mode. Maybe the time I'm away has something to do with the problem?
    – ZoFem
    Oct 19, 2017 at 8:37
  • Go into the Console (Utilities) and look for anything around the time of the shutdown. Also look for a phrase that says "shutdown cause"
    – Allan
    Oct 19, 2017 at 10:18


You must log in to answer this question.

Browse other questions tagged .