Use the same wallpaper on every desktop Space, or a different one on each

Why it happens

Your Mac can have several desktops, called Spaces, and each one can keep its own wallpaper. If you set a wallpaper while Show on all Spaces was off, it only changed the desktop you were on at the time. That's why swiping to another Space shows a different picture.

How to fix it

1. Choose Apple menu > System Settings and click Wallpaper in the sidebar.

2. Click the wallpaper you want to use everywhere.

3. Turn on Show on all Spaces. The picture now applies to every desktop Space you have.

   Wallpaper›Show on all Spaces

4. Swipe left or right with three or four fingers on the trackpad, or press Control-Right Arrow, to move to another Space and check it shows the same picture.

5. Prefer a different picture on each Space? Leave Show on all Spaces off, go to each Space in turn, and pick its wallpaper while you're there.

Still not fixed?

1. Have more than one display? Each screen has its own wallpaper. In Wallpaper settings, choose the display at the top, then set its picture.

2. If the picture changes by itself while you stay on one Space, you may have picked a shuffle or dynamic wallpaper. Those change on their own by design. Choose a still picture instead.

   Wallpaper

3. If each screen behaves differently with Spaces, check Displays have separate Spaces in Desktop & Dock, under Mission Control. Changing it needs you to log out and back in.

   Desktop & Dock›Mission Control›Displays have separate Spaces

4. If your wallpaper resets to the default every time you restart, even with Show on all Spaces on, contact Apple Support.