sudo killall coreaudiod: What It Does and When to Use It

If you have searched for a Mac sound problem, you have seen the advice: open Terminal and run sudo killall coreaudiod. It shows up in forum threads going back more than a decade, and people report that it works.

It is fair to want to know what a command does before typing your password into it. Here is what it does, when it helps, and when it is the wrong tool.

What coreaudiod Is

coreaudiod is the background service behind all sound on a Mac. Every app that plays or records audio goes through it. It keeps track of your speakers, headphones, and microphones, and it mixes the sound from different apps together.

The name is short for Core Audio daemon. A daemon is a program that runs in the background with no window.

What the Command Does

The command has three parts.

sudo runs what follows with administrator rights. That is why it asks for your password.
killall stops every running process with a given name.
coreaudiod is the name of the process to stop.

So the command stops the sound service. macOS starts a fresh copy as soon as anything asks for audio, usually within a few seconds. Nothing is uninstalled and no settings are erased. It is the audio equivalent of turning something off and on again.

How to Run It

Open Terminal (in Applications > Utilities, or search for it with Spotlight).
Type or paste this, then press Return:

sudo killall coreaudiod

Enter your Mac password and press Return. Nothing appears on screen as you type. That is normal.

Sound stops briefly and comes back. Apps that were playing may need you to press play again, and some need to be quit and reopened.

What Goes Wrong

“No matching processes belonging to you were found.” You left out sudo. The service belongs to the system and not to your account, so the command needs administrator rights.

“Sorry, try again.” The password was wrong. Use your own login password, and your account must be an administrator on this Mac.

Sound does not come back. Wait ten seconds, then check System Settings > Sound > Output and select your speakers again. After a restart of the service, macOS sometimes picks a different output. If there is still nothing, restart the Mac.

When It Helps

Restarting the sound service fixes problems where the service itself is in a bad state:

Crackling, popping, or stuttering that builds up over time
No sound from any app when the right output is selected and nothing is muted
A device that is connected but missing from the output list
Sound that does not return after the Mac wakes from sleep
Volume keys that move the slider without changing the loudness

When It Does Not Help

It cannot fix a problem that is not in the service.

The wrong output is selected. Sound is going to a display or to headphones in another room. See Mac sound not working.
The output controls its own volume. A monitor on HDMI ignores the Mac’s volume keys by design. See Mac volume not working.
An app lacks permission. A silent microphone in one app is usually a privacy setting. See Mac microphone not working.
The speaker is damaged. See MacBook speakers crackling for how to tell.

It is also temporary. If you need the command every day, something keeps putting the service into a bad state, and a third-party audio driver or an app that adds virtual devices is the usual suspect.

Is It Safe?

Yes, with one caution. Because all audio stops for a moment, a call can lose its audio until you rejoin, and a recording in progress is interrupted. Finish those first.

The command does not delete files or erase sound settings, though macOS may select a different output or microphone afterward. macOS restarts the service by itself. You do not need to start it again manually.

Doing It Without Terminal

There are two other ways to restart the service.

Activity Monitor. Open it, choose View > All Processes, search for coreaudiod, select it, and click the Stop button at the top of the window. Choose Force Quit, and enter an administrator name and password if asked.

Soundshine Doctor. Soundshine Doctor is our free Mac app, and restarting the sound service is the reason it exists. When a restart is what is needed, its Quick Fix button runs the same restart, with three differences from running the command by hand.

It checks first. If the Mac is muted, or the selected output is no longer connected, it fixes that instead of restarting something that is not broken.
It will not interrupt a call. If any app is using a microphone, Doctor refuses to restart until you are done.
It puts your output back. After the restart it selects the output you were using, and then asks how it sounds.

It still asks for your Mac password, because macOS requires administrator rights to restart this service. Doctor needs macOS 15 or later.

Download Soundshine Doctor free. No account, and Doctor never records audio.

Frequently Asked Questions

What does sudo killall coreaudiod do?

It stops coreaudiod, the background service that handles all sound on a Mac. macOS starts the service again by itself within a few seconds, which clears most stuck audio states. It is a restart of the sound system, not a change to your settings.

Is sudo killall coreaudiod safe?

Yes. It does not delete files or erase your sound settings, though macOS may select a different output or microphone afterward. The side effect is that all audio stops briefly, so a call can lose its audio until you rejoin and a recording in progress is interrupted. Finish those first.

Why does killall coreaudiod say no matching processes belonging to you were found?

You ran it without sudo. The service belongs to the system, not to your user account, so the command needs administrator rights. Run sudo killall coreaudiod and enter your Mac password.

Is there a way to restart Core Audio without Terminal?

Yes. You can force quit coreaudiod in Activity Monitor, or use the free app Soundshine Doctor, which restarts the sound service from a button and refuses to do it while any app is using a microphone.