Just updating a post from 2017 with the same issue & solution because it still applies several years and multiple versions later. It was difficult to track down and resolve. There's a *lot* of reasons a Macbook might not pay attention to power settings and sleep as expected. This happened after upgrading to Parallels 19.x. I'm 100% positive the setting wasn't changed by me (since I didn't even know it existed) which makes it likely the upgrade or other VM changes (e.g. switching to Coherence view full time) somehow checked the box. PROBLEM: My MacBook screen saver won't engage after the preset time interval when Parallels Desktop is running. When I look at the Energy tab on the Mac Activity Monitor it says Parallels Desktop is preventing sleeping. SOLUTION: I discovered "After upgrading to Parallels 13, my iMac display won 't sleep!" posted by user Ahwman in the Installation and Configuration forum. Low and behold, when I unchecked 'Allow apps to auto-switch to full screen' in VM config - Options - Applications as suggested by Parallels developer StanislavZ, Parallels Desktop showed up in the Mac Activity Monitor as not preventing sleep after restarting the desktop and things are back to working as they should! https://forum.parallels.com/threads/parallels-13-0-1-prevents-mac-from-sleeping.342043/
