What is coreaudiod on a Mac, and how to restart it when sound stops
coreaudiod runs all sound on a Mac. At rest it used no CPU and 5 to 18 MB here. Restarting it fixes most stuck audio, and it explains most audio CPU spikes.
What is coreaudiod?
It is the Core Audio daemon: every sound any app plays goes through it, and it manages every input and output device. It runs as its own user, _coreaudiod, from /usr/sbin/coreaudiod. On our Mac at rest it used 0.0% CPU and 5 to 18 MB.
How do I restart Core Audio?
sudo killall coreaudiodEnter your password. The sound system stops and macOS starts it again within a second or two. It fixes most cases of no sound, a device missing from the list, or crackling, without a restart. Apps playing sound may need to start playback again.
Why is coreaudiod using high CPU?
- An app holding audio open: a browser tab, a call app, a music app. Each stream costs work.
- Virtual audio devices: tools for recording system audio or routing sound between apps add drivers to
/Library/Audio/Plug-Ins/HAL. A misbehaving one shows up as coreaudiod CPU. - Sample rate changes: a device switching between rates many times, often a Bluetooth headset moving between music and call modes.
ls /Library/Audio/Plug-Ins/HALAnything listed there that you no longer use is worth removing with its own uninstaller.
See it live
Free Mac's System tab ranks every process by processor use and energy impact, once a second, and marks the ones macOS will not let you quit as protected. See also replayd for screen recording audio and audio plug-in formats.
Related: replayd and mediaanalysisd high CPU.
Common questions
What is coreaudiod on a Mac?
The Core Audio daemon, which carries all sound and manages audio devices. It runs as the _coreaudiod user.
How do I restart coreaudiod?
Run sudo killall coreaudiod in Terminal. macOS restarts it automatically within seconds.
Is it safe to kill coreaudiod?
Yes. It restarts on its own. Sound stops for a moment and apps may need to resume playback.