Strangely, there’s no single option in OS X which you can toggle to have your Mac automatically sign out after a certain period of inactivity. The functionality is still there though, you just have to adjust two settings. Here’s how:
- Open “System Preferences” and click “Desktop and Screen Saver.”
- Make sure that your screen saver is enabled, and choose how long you’d like your computer to wait before the screen saver starts.
- Go back to System Preferences and now click “Security & Privacy.
- Under the “General” tab you’ll see an option which says “Require password <length of time> after sleep or screen saver begins.” Choose “immediately.”