Show a screen saver after a given time to protect your on screen content. Even set a password so nobody can get into your Mac while you are away.How to fix itmacOS 10.11 – 11.0Go to “System Preferences” > “Desktop & Screen Saver”Click the Screen Saver tab. Screen savers appear on left side of the window, and a preview of the selected screen saver appears on the right.In “Start after” choose an suitable time. 5 or 10 Min is ok. (depends on your environment)Ensure in the Screen saver options, that your computer name is not shown.Require a password after the screen saver beginsGo to “System Preferences” > “Security & Privacy” > “General”“Require Password” xx seconds. Choose “immediately”.