Keyboard shortcut not working on your Mac? Find the conflict

A Mac shortcut comes from one of three places: macOS itself, the menus of the app in front, or another app that listens for keys in every app. When two of them want the same keys, one loses. Apple puts it plainly: a shortcut you assign that already exists for another command or app won't work until you change one of them.

Two quick checks first, both from Apple's guide to shortcuts that don't work:

• Function keys. If the shortcut uses F1 to F12, you may need to hold Fn or the Globe key as well, depending on your Mac, your keyboard and a setting in Keyboard settings.
• One app or all of them? Some shortcuts aren't available in some apps. Try it in another app; if it fails in only one, update that app and check its menus (below).

Where macOS keeps its shortcuts

Choose Apple menu › System Settings, click Keyboard in the sidebar, then click Keyboard Shortcuts. The shortcuts are grouped by category. On macOS 26.2 those are Dock, Display, Mission Control, Windows, Keyboard, Input Sources, Screenshots, Presenter Overlay, Services, Spotlight, Accessibility, App Shortcuts, Function Keys and Modifier Keys.

Apple's guide to changing a conflicting keyboard shortcut says a warning icon is shown next to conflicting shortcuts, and its troubleshooting page adds that the icon means another app is already using that shortcut. Click through the categories and look for it. Then:

1. Change it, or turn it off

   Double-click the shortcut and press new keys. Or, when an app needs those keys more than macOS does, deselect the shortcut's checkbox to turn the macOS one off, as Apple's guide to macOS keyboard shortcuts suggests.

2. Reopen your apps

   Quit and reopen the apps you're using for the change to take effect.

3. Start over if you need to

   Restore Defaults, in the bottom-left corner, puts every shortcut back to its original keys.

Check Modifier Keys while you're there. Each modifier can be set to act as another key or to do nothing, so if Command, Option, Control or Shift has been changed, every shortcut that uses it changes too (Apple's guide).

This list is macOS's own. Shortcuts that other apps set in their own settings, such as a launcher's or a window switcher's, aren't listed in System Settings, so a conflict with one of them may show no warning here. That's what the last section is for.

Spotlight and input sources

macOS uses the Space bar in several shortcuts, so an app's shortcut with Space can easily land on one of them. These are macOS's, from Apple's list of Mac keyboard shortcuts:

Apple's list adds that in some versions of macOS, if you use more than one input source, ⌘Space and ⌥⌘Space switch input sources instead, and it points to the conflicting-shortcut steps above. If you've added a language, check Input Sources before blaming the app.

Two related settings can make a key behave unexpectedly, both described in Apple's guide to writing in another language:

• The Fn or Globe key can be set to change input source when you press it alone, in Keyboard settings with Press fn key to.
• Caps Lock can switch between a Latin and a non-Latin input source, such as English and Chinese, if Use the Caps Lock key to switch to and from is on in Text Input › Edit. The option appears only once you've added a non-Latin input source.

App menu shortcuts

Every app can have its own shortcuts, and they're listed next to the commands in its menus. Apple's advice when a shortcut doesn't do what you expect is to look in the app's menus in the menu bar for the shortcut that actually applies there, since shortcuts can also vary with your language and keyboard layout.

If the menu shows the keys you pressed but something else happens, a macOS shortcut or another app has them. For a macOS shortcut, Apple's fix is the one above: change it or turn it off. For another app, see the last section.

You can also give a menu command your own keys, in Keyboard Shortcuts › App Shortcuts, for one app or for All Applications. Apple's guide to shortcuts for apps lists what trips people up:

• The keys are taken. A shortcut you create won't work if those keys already belong to another command or app.
• The menu title isn't exact. Type the command exactly as it appears, with -> between menu levels (Format->Font->Ligatures->Use Default) and three periods for an ellipsis. The macOS 14 guide also lets you type the ellipsis with ⌥;.
• It isn't a menu command. You can create shortcuts only for existing menu commands, not for tasks such as opening an app, and some apps don't allow shortcuts to be set.

Shortcuts you've created are listed under App Shortcuts. To remove one, select it and click the Remove button.

Apps that listen everywhere

Launchers, clipboard managers, window switchers and similar tools set shortcuts in their own settings that work in every app. They can clash with each other and with macOS. Two examples from their makers' sites: Contexts opens its search window with ⌃Space by default, the keys macOS uses to switch input sources, and AltTab uses ⌥Tab, the same keys as Flick's default.

1. List the suspects

   Look at the icons in your menu bar and the apps in your Dock. A tool that does something from anywhere when you press a key usually keeps that shortcut in its settings: open them and look for the keys you pressed.

2. Quit them one at a time

   Quit an app, try the shortcut, and move on to the next. For an app with no menu, use Activity Monitor: select it, click the Stop button and choose Quit.

3. Log in without login items

   Log out, then hold ⇧ while you click Log In and let go when the Dock appears. Apple's guide to login items says this keeps them from opening. If the shortcut works now, one of the items in General › Login Items & Extensions (Login Items in macOS 14 Sonoma) has it.

Two shortcuts have posts of their own: ⌘Tab not working and ⌘` not working.

With Flick

Flick is one of those apps that listen everywhere, so it checks its own keys and tells you when something else has them. Warnings appear in Flick's menu bar menu and at the top of Settings › Shortcuts, only while there's a conflict:

• “⌥Tab is in use by another app”. Another app registered the keys first, so Flick can't use them. Flick learns only that they're taken, not which app took them. The same warning can name ⌘Tab, the search shortcut, ⌘` or ⌥`.
• “AltTab also uses ⌥Tab”. A window switcher Flick recognizes is running, and its default shortcut is the same as Flick's.

Each warning offers only the buttons that apply: Use ⌘Tab Instead, Quit the other app, or Don't Warn About it once you've changed that app's keys. Flick never reads or changes another app's settings.

When you record Flick's search shortcut, a note under the field tells you if the keys usually belong to something else: ⌘Space for Spotlight, ⌃Space or ⌃⌥Space for input sources, ⌘ or ⇧⌘ with a letter or digit for menu commands. Flick's notes don't cover macOS 27's use of ⇧⌘Space, Flick's default search shortcut, for Siri AI. If you have Siri AI turned on, record a different search shortcut, as change the search shortcut shows.

How Flick's shortcut warnings work