Fix a Mac keyboard shortcut that does nothing or the wrong thing

Why it happens

Your Mac and your apps share the same keys, and when two shortcuts use the same combination only one of them wins. A system shortcut can also be switched off, changed, or broken by a remapped modifier key. For example, Control-Space can switch keyboard language, so an app that wants it never gets it.

How to fix it

1. Open the Apple menu, choose System Settings, click Keyboard, then click Keyboard Shortcuts….

   Keyboard›Keyboard Shortcuts…

2. Click each section in the list on the left, such as Spotlight, Input Sources, Mission Control and Screenshots, and look for the keys that misbehave.

3. Found the clash? Untick the shortcut you don't need. To give it new keys instead, double-click the keys shown and press the new combination.

4. For a shortcut inside one app, open App Shortcuts. You may have set different keys for that menu item there.

   Keyboard›Keyboard Shortcuts…›App Shortcuts

5. Click Done and try the shortcut again.

Still not fixed?

1. Copy and paste don't work anywhere? Open Modifier Keys and check that Command is set to Command. It may have been swapped with another key.

   Keyboard›Keyboard Shortcuts…›Modifier Keys

2. Put every shortcut back to how it came by clicking Restore Defaults in Keyboard Shortcuts.

   Keyboard›Keyboard Shortcuts…›Restore Defaults

3. If only one app ignores a shortcut, check its menus. Each item shows its keys on the right, and the app may use different ones than you expect.

4. If an app needs to catch your keys while you're in other apps, turn it on in Privacy & Security > Input Monitoring, then quit and reopen the app.

   Privacy & Security›Input Monitoring

5. Test the keys themselves in a plain text document. If one key never types and another keyboard works fine, that key is likely faulty, a hardware repair. For a built-in keyboard, contact Apple Support or a repair shop.