coreaudiod on Mac: what it is and why it uses CPU

What coreaudiod does

Core Audio is the sound system inside macOS, and coreaudiod is the daemon that runs it. Apps do not talk to the speakers. They hand audio to coreaudiod, which mixes every stream together, applies the volume and balance you set, resamples anything that does not match the output device, and pushes the result to whatever is selected: built-in speakers, AirPods, a USB interface, an HDMI display. It does the same in reverse for the microphone.

Because everything flows through one place, coreaudiod is also where virtual audio devices live. Tools like Loopback, BlackHole, Soundflower, Boom 3D and the audio devices installed by Zoom, Teams and screen recorders all plug into Core Audio as extra inputs or outputs. When one of them is active, coreaudiod does its work plus theirs.

What normal looks like

Why coreaudiod is using CPU right now

Work through these in order. The first three cover almost every report.

1. A virtual audio device is doing nothing useful. Boom 3D, Loopback, BlackHole and similar tools stay active even when you are not using them. In a 2025 Apple Community thread, one person traced 150 percent CPU on Sequoia to Boom 3D's virtual microphone; another found Recording Indicator Utility was the cause. Both went away when the tool was quit.
2. A meeting or screen-sharing app left its audio device open. Zoom, Teams, Discord and screen recorders open the microphone and a virtual output. If the app crashes or a call ends badly, coreaudiod can keep servicing a device nobody is listening to.
3. Audio plug-ins in a music app. Logic, GarageBand, Ableton and their Audio Units can run processing inside Core Audio. A heavy plug-in chain is normal work, not a fault.
4. Many browser tabs with media. Every tab that has played sound keeps an audio stream open. Twenty tabs is twenty streams to mix.
5. Sample rate mismatch. If your output device runs at 48 kHz and an app insists on 44.1 kHz, coreaudiod resamples every buffer. Audio MIDI Setup shows the rates.
6. A stale state after sleep or a device unplug. Unplugging a USB interface or HDMI display mid-stream sometimes leaves the daemon spinning. A restart of the daemon clears it.

Is it safe to quit coreaudiod?

Quitting coreaudiod from Activity Monitor is harmless, and it is the one system daemon on this site where doing so is a reasonable troubleshooting step. Sound stops for about a second, launchd starts a fresh copy, and every app reconnects on its own. You lose nothing. What you do not gain is a fix: if a virtual device or stuck app caused the load, the new coreaudiod picks up the same device and climbs again within a minute. So quit it once to confirm the symptom clears, then go find the cause. Do not use Terminal and sudo for this; Activity Monitor does the same thing without the risk of a typo hitting the wrong process.

Other audio-related names you might see next to it: audioaccessoryd (AirPods and Beats), AudioComponentRegistrar (plug-in scanning), avconferenced (FaceTime and SharePlay). Type any of them above.

What to do, in order

1. Quit every app that touches audio

   Music, Spotify, the browser, Zoom, Teams, Discord, any screen recorder, any music app. Watch coreaudiod in Activity Monitor for thirty seconds. If it drops, reopen apps one at a time until it jumps. That app is the cause.

2. Check for virtual audio devices

   Open Audio MIDI Setup (in Applications, Utilities). Anything in the list that is not your speakers, microphone, headphones or a physical interface is a virtual device. Quit the app that installed it, or uninstall it if you no longer use it.

3. Look for a recording indicator or audio utility in the menu bar

   Recording Indicator Utility, Boom, SoundSource, Background Music, eqMac and similar helpers sit in the menu bar and keep a device open. Quit them and watch coreaudiod.

4. Restart coreaudiod from Activity Monitor

   Select coreaudiod, click the stop button in the toolbar, choose Quit. Sound returns within a second or two. This clears a stale state after sleep or an unplugged device.

5. Match sample rates

   In Audio MIDI Setup, select your output device and note its format (for example 48,000 Hz). Set music and meeting apps to the same rate where they let you. This removes continuous resampling.

6. Restart the Mac and update macOS

   If it still climbs with every audio app closed, a restart resets the audio stack completely. Then check Software Update: several coreaudiod bugs over the years were fixed in point releases.

When to worry

Worry if coreaudiod stays above 50 percent with every audio app closed, Audio MIDI Setup showing only physical devices, and a fresh restart behind you. That is rare and points to a third-party audio driver that loads at boot; System Settings, General, Login Items & Extensions lists them. Worry if the fans run hard with nothing playing and coreaudiod is the top row: that is the same thing with a louder symptom. Do not worry about 5 to 12 percent during a call, 20 to 40 percent with a music production session open, or a brief spike when you plug in headphones. All of that is coreaudiod doing exactly its job.

If you want this answer for whatever process is on top right now, Safe to Quit shows the verdict next to each name so you can stop guessing.