In my newish Mojave install on an iMac I experience some odd behaviour:

⌥ Option⌘ Command] plays the alert sound even if it is bound to an action in a keyboard shortcut tool like Keyboard Maestro

And it is only ⌥ Option⌘ Command], other key combinations which (to my knowledge) are not bound to anything. E.g ⌥ Option⌘ Command[ doesn't make any sound.

Also this behavior only seems to happen in one (my main) user account (other accounts - whether admin accounts or not) do not have this problem.

I cannot attribute this to any main application or menu bar app. (And I have quite a few of them!) How did I check?: One-by-one I quit all main apps and then all menu bar apps - still ⌥ Option⌘ Command] plays the alert sound.

How can I find out what causes this alert tone? How can I find out which app/tool/daemon binds to ⌥ Option⌘ Command]?


I care about this because I usually have on ⌥ Option⌘ Command] a particular Keyboard Maestro macro running. This still works - but additionally this unexpected alert sound plays on the shortcut. (And the sound happens even if I have Keyboard Maestro completely quit.)

  • Any menu bar item blinks when you press that ?
    – anki
    Commented Mar 29, 2020 at 6:07
  • @ankii No. The beep even happens when I quit all menu bar apps. %-/
    – halloleo
    Commented Mar 29, 2020 at 7:47
  • Is it the same sound that happens when you hit cmd + w 5-6 times on Finder ? If so, it's an indicator of nothing happening. like an 404 error.
    – anki
    Commented Mar 29, 2020 at 8:01
  • 1
    Also, see this answer for a tool to help you find it. There's two options a paid utility with a free trial and a completely free utility - both can help you track it down.
    – Allan
    Commented Apr 5, 2020 at 3:24
  • 1
    Also, since you don't have the issue in other accounts and you don't see anything in Login Items, use the following command and past the output to to pastebin (or similar) and link back to your question. This way we can see what's getting loaded. launchctl list
    – Allan
    Commented Apr 5, 2020 at 3:30

4 Answers 4


Shortcut Detective from Irradiated Software's labs page should tell you exactly what is picking up this keypress.

ShortcutDetective detects which app receives a keyboard shortcut (hotkey).

  • This is some neat software and thanks for the link! But t as stated on their page and in the link of my comment - see apple.stackexchange.com/a/387057/119271 - not all shortcuts can be detected if the app doesn't register it.
    – Allan
    Commented Apr 7, 2020 at 1:32
  • Thanks @John Noble. Will check it out today and report back.
    – halloleo
    Commented Apr 9, 2020 at 2:12
  • ShortcutDetective found it! It was Copied which hogged the shortcut. But because I run it as a Menu-Bar-only app the shortcut did show up in KeyCue! ShortcutDetective is a great tip!
    – halloleo
    Commented Apr 9, 2020 at 12:29

I would go into system preferences > keyboard > shortcuts, and browse through all of the keyboard shortcuts and see if any have ⌘⌥]as they’re keybind. you could also open Automator, and press the record button, press ⌘⌥] and then click stop recording and see what it says that you did.

  • Good suggestion. However none of the shortcuts in the System preferences has ⌘⌥] assigned to it.
    – halloleo
    Commented Apr 5, 2020 at 2:43
  • Also recording the key stroke in Automator gives me back an empty Watch Me Do action. (However recording another keystroke e.g. ⌘⌥[ fives me a Watch Me Do action with the "Press ⌘⌥[" event! - There's clearly something going on with ⌘⌥].)
    – halloleo
    Commented Apr 5, 2020 at 3:03
  • It may be somewhat bound to the '⌘[' or '⌘]' go back/forward shortcuts. I'm assuming that you are an admin on your Mac. if you go to >sign out, and press '⌘⌥]'. Are you using an apple keyboard or a 3rd party one. Commented Apr 6, 2020 at 2:30
  • I use an Apple Keyboard. What do you mean with "if you go to >sign out, and press '⌘⌥]'"? - I don't understand.
    – halloleo
    Commented Apr 6, 2020 at 6:36
  • @halloleo the  menu at the side of the menu bar sorry I forgot to put menu Commented Apr 6, 2020 at 14:21

If you just want the 'bonk' sound to stop then go to System Preferences > Sound and move the Alert Volume slider to the left. In this case you might miss out on other alerts mac tries to tell you.

  • 1
    This is not really a fix for me: I need to the Alarm sound for audible feedback in many other circumstances.
    – halloleo
    Commented Apr 5, 2020 at 2:44

This doesn't apply to your situation with macOS Mojave, but might be helpful for future viewers.

If you're using macOS Catalina (10.15) or newer and you're wondering about applications that might be intercepting specific key combinations, look at the list of applications that have the Input Monitoring permission granted in Security & Privacy settings.

That, combined with the standard keyboard shortcuts, should account for all the different ways that global hotkey keyboard shortcuts can be installed.

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