Why Your Mac Keyboard Shortcut Stopped Working (And How to Fix It)

A keyboard shortcut that worked yesterday and does nothing today is one of the most annoying small failures on a Mac, because the system gives you zero feedback. No error, no beep, no log entry you’d ever think to look at. The keystroke just vanishes.

The good news: almost every dead shortcut has one of seven causes, and they’re easy to check once you know the order. This checklist runs from most likely to least likely. Work it top to bottom and you’ll usually find the culprit at step one or two.

1. Another app stole the combo (the big one)

This is the cause in the clear majority of cases, and it’s worth understanding why.

macOS lets any app register global hotkeys — shortcuts that work system-wide, regardless of which app is focused. Launchers, clipboard managers, screenshot tools, window managers, and screen recorders all do this. The precedence rules:

• A global hotkey consumes the keystroke before the frontmost app sees it. If a utility registers ⌘⇧V globally, “Paste and Match Style” silently dies in every app on your Mac.
• When two apps register the same global hotkey, the one that registered last usually wins — which in practice means the app you launched, installed, or updated most recently.

That last point explains the classic pattern: your shortcut worked for months, then died the same week you installed some unrelated utility. The new app grabbed the combo on launch and nothing told you.

How to find the thief. You can audit every hotkey-capable app’s settings by hand (slow — see the full rundown of manual methods), or scan everything at once with HotkeyClash, a free, open-source menu bar utility for macOS 14+. One scan reads every running app’s menu shortcuts via the Accessibility API, your Karabiner-Elements and skhd configs, and the macOS symbolic hotkeys, then flags every combo claimed more than once. A real scan covers ~700 shortcuts in about three seconds. Find your dead combo in the results and you’ll see exactly who else holds it:

• Definite (red): two global hotkeys on the same combo — guaranteed clash.
• Potential (amber): a global hotkey overlapping an app’s menu shortcut — only clashes when that app is focused, which is why some shortcuts fail “only sometimes.”

The fix. Rebind the combo in whichever app you care about less — in that app’s own settings, since well-behaved tools (HotkeyClash included) don’t rewrite other apps’ configurations. Install HotkeyClash from the download page.

If this step doesn’t explain it, continue down the list.

2. The shortcut was disabled or changed in System Settings

macOS system shortcuts (Spotlight, Mission Control, screenshots, input sources, and dozens more) live in System Settings → Keyboard → Keyboard Shortcuts. Each one has a checkbox and an editable key combo, and it’s easy for either to change — by you, months ago, or by software that modifies these settings.

Check: open the category your shortcut belongs to (e.g., Screenshots for ⌘⇧5) and confirm the entry is both enabled (checkbox ticked) and bound to the combo you expect (double-click to rebind). Yellow warning triangles in this pane mark conflicts among system shortcuts — though note this pane knows nothing about third-party apps.

Fix: re-tick the checkbox or rebind, or click Restore Defaults in the relevant section to reset that category wholesale.

3. The app is missing Accessibility or Input Monitoring permission

Many shortcut-driven utilities — window managers, text expanders, automation tools — can only do their job with Accessibility and/or Input Monitoring permission. If that permission was never granted, was revoked, or got reset, the app’s hotkeys silently stop working even though the app looks fine.

Check: System Settings → Privacy & Security → Accessibility, and separately → Input Monitoring. Confirm the affected app is listed and toggled on.

Fix: toggle the permission on. If it’s already on but the app still misbehaves, toggle it off and on again, or remove the app from the list with the minus button and re-add it — stale permission entries are a real thing, especially after app updates change the binary’s signature.

Sequoia note: macOS Sequoia is stricter about these permissions than earlier releases and re-prompts for some of them periodically. After a macOS update, treat “all my utility’s shortcuts died at once” as a permissions symptom until proven otherwise.

4. A Karabiner or remapping rule intercepts the key first

Karabiner-Elements, skhd, BetterTouchTool, and similar tools sit in front of the regular event pipeline. A remapping rule rewrites or consumes the keystroke before any app — or macOS itself — sees the original. A rule you added for one purpose can shadow an unrelated shortcut, and complex modifications in ~/.config/karabiner/karabiner.json make this easy to forget.

Check: the brute-force test is to quit Karabiner-Elements (and skhd, if you run it) and try the shortcut again. If it springs back to life, a rule is responsible. To find which rule without trial and error, a HotkeyClash scan includes both karabiner.json and ~/.config/skhd/skhdrc as first-class sources, so config-defined bindings show up in the same conflict list as app hotkeys.

Fix: edit or disable the offending rule in Karabiner-Elements’ settings (Complex Modifications) or directly in the config file.

5. A per-app shortcut override in App Shortcuts

System Settings → Keyboard → Keyboard Shortcuts → App Shortcuts lets you override any menu item’s shortcut, either for “All Applications” or one specific app. These overrides are powerful and very easy to forget — an entry added a year ago can silently rebind or shadow a menu shortcut, and the app’s own menus will even display the overridden combo, adding to the confusion.

Check: open App Shortcuts and review every entry, especially anything under “All Applications.”

Fix: select the stale entry and remove it with the minus button. The menu item reverts to the app’s default shortcut immediately (you may need to relaunch the app).

6. Stuck modifiers, hardware, or Bluetooth keyboard issues

Less common, but real — and worth ruling out before deeper digging:

• Stuck modifier state. If every shortcut behaves strangely (e.g., typing letters triggers commands), a modifier key is stuck — physically, or logically via Sticky Keys. Tap each modifier (⌘ ⌥ ⌃ ⇧ fn) a few times, and check System Settings → Accessibility → Keyboard → Sticky Keys.
• Bluetooth keyboards drop and re-pair, and occasionally reconnect in a degraded state where modifiers misreport. Toggle Bluetooth off and on, or re-pair the keyboard.
• Third-party keyboards may have their own firmware layers (Fn lock, layer keys on mechanical boards) that remap or swallow combos. Check Modifier Keys mapping under System Settings → Keyboard → Keyboard Shortcuts → Modifier Keys, which is set per keyboard.
• Test in another user account. If the shortcut works in a fresh account, the cause is in your account’s settings or login items, not hardware.

7. A macOS update reset the symbolic hotkeys

System shortcuts are stored in a per-user plist of “symbolic hotkeys.” Major macOS updates occasionally reset customized entries to defaults or re-enable shortcuts you had deliberately disabled — which manifests either as your custom shortcut reverting, or as a new conflict because a re-enabled system shortcut now collides with an app hotkey you set up while it was off.

Check and fix: after any macOS update, skim System Settings → Keyboard → Keyboard Shortcuts for entries that changed, and re-apply your customizations. Since the symbolic hotkeys plist is one of HotkeyClash’s three scan sources, a post-update scan is a quick way to spot re-enabled system shortcuts that now clash with your apps — they’ll show up as new red or amber entries.

Quick reference

#	Cause	Fastest check
1	Another app registered the combo globally	HotkeyClash scan; search for the combo
2	Disabled/changed in System Settings	Keyboard → Keyboard Shortcuts, check the entry
3	Missing Accessibility/Input Monitoring permission	Privacy & Security; toggle off and on
4	Karabiner/skhd rule intercepts the key	Quit the remapper and retest; scan configs
5	App Shortcuts override	Keyboard Shortcuts → App Shortcuts; delete stale entries
6	Stuck modifier / hardware / Bluetooth	Tap modifiers; re-pair; test another account
7	macOS update reset symbolic hotkeys	Re-check Keyboard Shortcuts after updates; re-scan

The bottom line

Dead shortcuts on a Mac are almost never mysterious — they’re just invisible. The keystroke goes somewhere; macOS simply won’t tell you where. Step 1 covers most cases, and it’s also the fastest to check: a single HotkeyClash scan maps every registered shortcut from running apps, config files, and macOS itself in about three seconds, entirely offline. If the scan comes back clean for your combo, steps 2 through 7 will catch the rest — permissions, overrides, and the occasional stuck ⌘ key.