I did some testing about activities which prevent sleep on Mojave:
It seems that when the display shows a moving image, even if on a background app (such as a youtube video mostly stopped by Finder but still showing movement) prevents sleep, a similar video with a static image but playing audio slept the display (and locked the mac) but didn’t sleep the mac. If the video is playing on another hidden tab, the mac screen or the mac itself (not sure what happened) went to sleep once, not another. No app, nor safari, showed in activity monitor as preventing sleep.
So I wonder
- Will the mac go to sleep if you let it running a long youtube video?
- Will the mac go to sleep if it has a cloud app enabled (google drive/dropbox/iCloud drive…)
- What other activity can prevent a mac from sleeping?
I'm looking for in-depth answers which explain which activities enable or disable sleep on Mojave.