The Unwanted Blackout
macOS is heavily optimized for energy efficiency. To conserve battery life and prevent screen burn-in on older monitors, the operating system will automatically turn off your display after a few minutes of inactivity. While this is generally beneficial, it can become a significant annoyance during specific tasks. If you are reading a long article without touching the trackpad, giving a presentation, or simply trying to monitor a slow-moving progress bar from across the room, having the screen suddenly go black—often requiring you to re-enter your password to wake it back up—is incredibly disruptive to your workflow.
Extending the Timeout
To ensure your screen remains visible for as long as you need it and stop macOS from automatically turning off the display, you must adjust the energy saving parameters in your system settings.
Click the Apple logo in the extreme top-left corner of your screen and select System Settings. In the left-hand navigation sidebar, scroll down and click on Lock Screen (on older macOS versions, look for “Energy Saver” or “Battery”). On the right-hand panel, look for the dropdown menu explicitly named Turn display off on battery when inactive and its counterpart, Turn display off on power adapter when inactive. Click these dropdown menus and change the timeout duration from the default (usually 2 or 5 minutes) to a longer period, such as 1 Hour, or select Never if you want the screen to stay on permanently until you physically close the lid. Note that selecting “Never” will prompt a warning about reduced battery life.