I have a 2017 iMac with macos Mojave installed. (fresh install)
The imac has the energy settings set to never sleep, only to turn off the screen after 15 minutes.
Lately I have found that the iMac does in fact go to sleep once the screen turns off, and starts up again when I hit the spacebar to wake up the screen (or vnc in)
Any ideas on how this happens? And how I can force it to stay awake?
It’s driving me nuts that even though the settings say it is supposed to stay awake it still goes to sleep…
Is it possible you have “Put hard discs to sleep when possible” checked?
Yes, check the Energy Saver settings for HD sleep, and Power Nap.
I sometimes use the Amphetamine app to keep my Mac awake for a defined period of time. It’s a very flexible app and is available on the Mac App Store for the very affordable price of FREE.
Probably a corrupt plist file, resetting fixed it.
I reset the settings in the energy screen (unchecked and checked them again) and restarted the machine, now everything is as it should be…