Stop your Mac switching to Dark Mode on its own

Why it happens

With Appearance set to Auto, your Mac follows the sun: it goes dark around sunset and light again in the morning. Auto is often picked during setup without people noticing.

How to fix it

1. Open the Apple menu, choose System Settings and click Appearance in the sidebar.

2. In the Appearance row at the top, click Light or Dark. Auto is the one that changes by itself.

   Appearance

3. Close System Settings. Menus, windows and the Dock now stay on your choice, day and night.

Still not fixed?

1. Wallpaper still changing through the day? It's a dynamic wallpaper. Open Wallpaper and set it to Light (Still) or Dark (Still).

   Wallpaper

2. Only the app icons and widgets look dark? That's Icon & widget style, a separate setting in Appearance.

   Appearance›Icon & widget style

3. Screen turns warm or yellow in the evening? That's Night Shift, not Dark Mode. Change its schedule in Displays.

   Displays›Night Shift…

4. One app stays dark or light whatever you pick? Some apps have their own theme setting. Look in that app's Settings.

5. If you use Shortcuts automations, check that none of them changes the appearance at a set time.

6. If your Mac still switches with Light or Dark chosen, check whether a school or company manages it. If not, contact Apple Support.