MacBooks can be connected to an external display so that you can extend the screen or use the larger external monitor as your primary display.
On a laptop running the Windows operating system, when you connect it to an external display and select it as the primary/main screen, the laptop’s screen is automatically turned off to save power and avoid distraction. However, when a MacBook is connected to an external monitor and the external monitor is the main display (under Settings > Displays page), the MacBook Air or Pro screen continues to turn on.
In other words, when using the connected external monitor as your main screen, your MacBook’s screen is not automatically turned off. This is not a problem for users who use an external mouse and keyboard as they can always close the MacBook lid (which turns off the screen but does not put the Mac to sleep mode when connected to an external display) and continue working.
Users who use the MacBook’s keyboard and trackpad (instead of an external keyboard and mouse) when connected to an external display might want to turn off the MacBook’s screen so that they can save the battery and also stop the MacBook’s screen from distracting them.
Unfortunately, the macOS System Settings does not offer an option to automatically turn off the screen when using an external display as the main screen. However, there is a workaround!
Turn off the MacBook’s screen when using an external display as the main screen
Although macOS does not let you turn off the screen, you can always bring down the screen brightness to zero to make it look like a turned-off screen. This way, you can avoid distraction and save some battery power.
You can use the dedicated function key or navigate to System Settings > Displays to manually adjust the screen brightness.
Use a third-party app to turn off the MacBook screen when connected to an external screen
If you do not like the above idea of reducing the screen brightness to make your Mac’s screen look turned off, you can use third-party tools such as Lunar to turn off your MacBook’s screen when connected to an external monitor.
You can download the Lunar app (paid) from this official page.
Our how to automatically turn off MacBook trackpad when a mouse is connected guide might also interest you.
Leave a Reply