macOS features a highly customizable shortcut system known as “Hot Corners.” By moving your mouse cursor to one of the four extreme corners of your screen, you can trigger specific actions, such as showing the desktop or opening Launchpad. However, a common default—or accidental configuration—is setting a Hot Corner to “Lock Screen” or “Put Display to Sleep.”
If you have this enabled, accidentally brushing your mouse against the bottom-left corner of your monitor will instantly plunge your Mac into darkness and demand your password to unlock it. If you use full-screen applications or frequently move your mouse quickly across a large monitor, you will constantly trigger this infuriating lockdown.
You can easily reconfigure or completely disable Hot Corners to stop this behavior.
How to Disable the Lock Screen Hot Corner
You can remove or change the Hot Corner assignments from the System 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 Desktop & Dock.
- Scroll all the way down to the very bottom of the right pane and click the Hot Corners… button.
- A small dialog box will appear showing four drop-down menus representing the four corners of your screen.
- Locate the drop-down menu that currently says Lock Screen or Put Display to Sleep.
- Click the menu and change it to the hyphen (-) symbol (which means “Do Nothing”).
- Click Done.
Your Mac will immediately stop reacting when you ram your mouse cursor into that corner of the display, allowing you to work without fear of accidental lockouts.