Is there a shortcut to change the main display on a Mac?

No. macOS has no keyboard shortcut for it. Use System Settings, Displays, Arrange, or save a displayplacer command and run it from a shortcut you set up.

How do I move the Dock to my other monitor on a Mac?

Make that monitor the main display, or turn on Displays have separate Spaces in Desktop & Dock and move the pointer to the bottom edge of the other screen until the Dock appears there.

How do I make my external monitor the main display on a MacBook?

In System Settings, Displays, click Arrange and drag the white menu bar onto the external monitor. The menu bar and Dock move there, and it stays the main display while the same screens are connected.

Why does my Mac keep switching the main display back to the MacBook?

After a wake or reconnect, docks and identical monitors can come back in a different order, so macOS applies the wrong arrangement. A tool such as displayplacer or DisplayShift reapplies yours.

How do I move the menu bar to my second monitor?

Drag the white bar in System Settings, Displays, Arrange onto the second monitor. That makes it the main display, so the Dock moves with it.

Do open windows move when I change the main display?

No. Changing the main display moves the menu bar and Dock, but windows that are already open stay on the screen they're on. Drag them across, or use a tool such as DisplayShift to move them all at once.

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Mac guide

How to make an external monitor the main display on a Mac

By Aqib Javed · Updated Nov 2, 2026

To make an external monitor the main display on a Mac, open System Settings, click Displays, click Arrange, and drag the white menu bar from the MacBook screen onto the monitor, then click Done. You can also select the monitor in Displays and set Use as to Main display. The main display gets the menu bar and the Dock, and macOS saves the choice for that set of screens.

How to change the main display

Connect the monitor and make sure it's extending your desktop, not mirroring it.
Open System Settings and click Displays in the sidebar.
Click Arrange. Each screen appears as a box, and the main display has a white bar along its top: that is the menu bar.
Drag the white bar onto the monitor's box. The menu bar and Dock jump to the monitor.
Click Done.

The other way: in Displays, click the monitor's name and open the Use as pop-up menu, which offers main display, extended display and mirroring. There's no built-in keyboard shortcut for switching the main display.

Moving the Dock and menu bar to the other monitor

The Dock follows the main display. With Displays have separate Spaces off (System Settings, Desktop & Dock), the Dock appears only on the main display.
With Displays have separate Spaces on, the Dock is available on every display: move the pointer to the bottom edge of the other screen and hold it there, and the Dock moves over.
With separate Spaces on, each screen also shows its own menu bar, but the main display is still the one macOS treats as primary.
Changing Displays have separate Spaces takes effect after you log out and back in.

Use only the external monitor

If you want the monitor to be the only screen, close the MacBook's lid. That's clamshell mode, and it needs power plus an external keyboard and mouse or trackpad; the clamshell mode guide covers the details. Mirroring both screens is the other option, but it limits the monitor to a picture the MacBook can also show.

Make it stick after sleep and reconnecting

macOS remembers the main display for each set of screens, but it can lose track after a plug-in or wake, especially with docks, DisplayLink adapters or two identical monitors, and the menu bar ends up back on the MacBook. The guide on Macs swapping monitor arrangements explains why.

displayplacer, a free command line tool, can reset it: the screen at origin (0,0) in its command becomes the main display. Run displayplacer list, then save the command it prints at the bottom and run it whenever the arrangement changes.

DisplayShift does this without commands. With Keep my screen arrangement on (Settings, Screens), it learns the arrangement and main display you set yourself and puts them back if macOS swaps them after a plug-in or wake. It doesn't choose the main display for you; you still set it in System Settings once. It's free for 7 days, then $6.99 once.

brew install displayplacer
displayplacer list

Questions

Is there a shortcut to change the main display on a Mac?: No. macOS has no keyboard shortcut for it. Use System Settings, Displays, Arrange, or save a displayplacer command and run it from a shortcut you set up.
How do I move the Dock to my other monitor on a Mac?: Make that monitor the main display, or turn on Displays have separate Spaces in Desktop & Dock and move the pointer to the bottom edge of the other screen until the Dock appears there.
How do I make my external monitor the main display on a MacBook?: In System Settings, Displays, click Arrange and drag the white menu bar onto the external monitor. The menu bar and Dock move there, and it stays the main display while the same screens are connected.
Why does my Mac keep switching the main display back to the MacBook?: After a wake or reconnect, docks and identical monitors can come back in a different order, so macOS applies the wrong arrangement. A tool such as displayplacer or DisplayShift reapplies yours.
How do I move the menu bar to my second monitor?: Drag the white bar in System Settings, Displays, Arrange onto the second monitor. That makes it the main display, so the Dock moves with it.
Do open windows move when I change the main display?: No. Changing the main display moves the menu bar and Dock, but windows that are already open stay on the screen they're on. Drag them across, or use a tool such as DisplayShift to move them all at once.