CrackMacHow to turn off your MacBook screen and use only an external monitor
The built-in way is to close the lid. With power, an external monitor and a keyboard and mouse connected, a MacBook runs in clamshell mode and uses only the monitor. macOS has no setting to switch the laptop screen off with the lid open. For that you need a third-party display utility, or one of the workarounds below.
Lid closed: clamshell mode
- Connect the power adapter, the monitor, and a keyboard and mouse or trackpad.
- Wait for the monitor to show the desktop.
- Close the lid. The built-in screen turns off and everything moves to the monitor.
The full setup and fixes for a monitor that won't wake are in clamshell mode.
Lid open, built-in screen off
This is handy if you want to use the MacBook's own keyboard and trackpad. macOS can't do it alone. Your options:
- A display utility. BetterDisplay can disconnect the built-in display on Apple silicon Macs, which removes it from the layout entirely. That feature needs its paid version.
- Mirroring plus zero brightness. Press Command-Brightness Down to mirror, then turn the built-in brightness to zero. The screen goes dark, but macOS still treats it as a display.
- Brightness to zero, extended. The screen goes dark, but windows and the pointer can still wander onto it, which gets confusing fast.
One catch with two monitors
On base M3 MacBook Air and 14-inch MacBook Pro models, two external displays only work with the lid closed. Disconnecting the built-in screen in software doesn't free up the second connection. See monitor not detected for each Mac's limit.
If the built-in screen is only partly broken
Switching it off throws away a screen that's mostly fine. If the damage is a strip along one edge, keep the rest in use instead.
If the damage runs along one edge, CrackMac can keep windows, menus and the pointer off it. There's a free 30-minute trial.
Quick answers
Can I turn off my MacBook screen and keep using an external monitor?
Yes. The built-in way is clamshell mode: connect power, the monitor and a keyboard and mouse, then close the lid. To keep the lid open with the built-in screen off, you need a display utility that can disconnect it, such as BetterDisplay.
Does macOS have a setting to disable the built-in display?
No. macOS has no switch for it. Turning the brightness all the way down blanks the screen, but macOS still counts it as a display, so windows and the pointer can still go there.
Only part of the built-in screen is broken?
Then you don't have to switch it off. CrackMac blacks out the damaged strip and keeps windows, menus and the pointer on the rest, so the laptop screen keeps working as a second display or on the go.
- Works on macOS 13 or later, Apple silicon and Intel.
- Free for 30 minutes of use, then a one-time price. No subscription.
- A refund within 7 days, no questions asked.