I'm trying to use an auxiliary LCD as a light-pad/bed/table by loading up a 1080p white .PNG in preview and setting fullscreen ON.

The problem is after several (20?) minutes of inactivity I get the Apple screensaver kicking in, and then have to enter my password.

How to prevent this?

Nothing in System Prefs -> Energy Saver works.

http://osxdaily.com/2011/03/21/temporarily-prevent-a-mac-from-sleeping/ suggests pmset noidle but that's also fails.

  • 1
    Does System Preferences -> Desktop and Screensaver -> Screensaver not work?
    – JMY1000
    May 25, 2016 at 15:50
  • @JMY1000, thanks, this is the answer! And my bad for being really blind.
    – P i
    May 25, 2016 at 16:40

3 Answers 3


Screen Saver is under System Preferences > Desktop & Screen Saver > Screen Saver, not System Preferences > Energy Saver. Simply navigate to this preference pane, then in the bottom left corner, select the Start after: menu and choose Never.

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In addition to the "sleep corner" mentioned in Tetsujin's answer, there is also a small app out there called Caffeine which you can use to prevent the machine (and thus display as well) from sleeping. Note that it will even stop a laptop from sleeping when the lid is shut, so be sure to disable it. There are also alternatives like Amphetamine and Owly that seem to do the same thing, but I've only use Caffeine. All of them hit the same underlying OSX setting, apparently.


Try System Prefs > Desktop & Screen Saver > Hot Corners.

I have mine set like this... just shove the cursor to the top left of the main screen & no more nodding off...

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