For enhanced security in corporate environments, macOS includes a feature that automatically logs you entirely out of your user account if the computer remains idle for a predetermined amount of time. When you return to your desk, you are not just greeted by the lock screen; you find that all your applications have been forcefully closed, all your active terminal sessions have been terminated, and you are staring at the primary user login window.
While this is an excellent security policy for a shared laboratory computer or a kiosk, it is absolutely infuriating on a personal MacBook. If you step away to eat lunch while your Mac is slowly rendering a massive video file or compiling a large codebase, having the operating system automatically log you out will instantly kill the render, destroying hours of background work.
You can dive into the advanced privacy settings to completely disable the automatic logout timer, ensuring your user account remains persistently active.
How to Stop macOS from Logging You Out
You must turn off the idle logout feature hidden inside the Advanced settings.
- Open the System Settings (or System Preferences) via the Apple Logo in the top-left menu bar.
- Scroll down the left sidebar and click on Privacy & Security.
- Scroll all the way down to the very bottom of the right-hand pane.
- Click the button labeled Advanced… (You may be prompted to enter your Mac administrator password to proceed).
- A small dialog box will appear. Look for the checkbox labeled Log out automatically after inactivity.
- Uncheck this box.
- Click OK to save your changes.
macOS will immediately disable the aggressive logout timer. If you leave your computer running, it may eventually put the display to sleep or trigger the screen saver, but your user session—and all your background applications—will remain safely running until you explicitly choose to shut down.