Stop Spaces from rearranging automatically on Mac

macOS shuffles your Spaces into a new order every time you switch between them, based on "most recent use." If you've arranged Space 1 for email, Space 2 for code, Space 3 for Slack, this behavior constantly scrambles that layout. One toggle fixes it.

Why Spaces rearrange

A feature called Automatically rearrange Spaces based on most recent use is on by default. macOS tracks which Spaces you visited most recently and floats them to the front of the Mission Control strip. The idea is to surface the things you're actively using — but it destroys any deliberate layout you've set up.

Turn it off in System Settings

1. Open System Settings → Desktop & Dock.
2. Scroll down to the Mission Control section.
3. Turn off "Automatically rearrange Spaces based on most recent use".

Your Spaces now stay in exactly the order you arranged them in Mission Control. Drag them in the Mission Control strip to set the order you want, and they'll hold it.

The Terminal command

The underlying key is mru-spaces in com.apple.dock:

# disable automatic Spaces rearranging
defaults write com.apple.dock mru-spaces -bool false
killall Dock

To re-enable it:

defaults write com.apple.dock mru-spaces -bool true
killall Dock

Setting a fixed Space order

Once auto-rearrange is off, open Mission Control (swipe up with three fingers, or press ⌃↑). You'll see your Spaces strip at the top. Drag the thumbnails left and right to put them in whatever order makes sense for your workflow. That order persists now that macOS is no longer reshuffling them.

Combine it with fixed app assignments

For the most stable layout, assign specific apps to specific Spaces: right-click (or Control-click) an app's Dock icon → Options → Assign To → select a Space. The app always opens on that Space, and with auto-rearrange off, that Space stays where you put it.