In macOS, every sound you hear—from a YouTube video to a system notification ping—is routed through a low-level background system daemon known as coreaudiod (Core Audio Daemon). If you constantly switch between Bluetooth headphones, an external monitor with built-in speakers, and your Mac’s internal speakers, the routing tables inside this daemon can become confused and crash.
When the CoreAudio daemon crashes, your Mac might refuse to play any sound at all, the volume buttons on your keyboard might display a grey “prohibited” symbol when pressed, or your speakers might emit a constant, terrifying crackling static noise. You can instantly fix this without rebooting your Mac by manually forcing the daemon to restart via the Terminal.
How to Manually Restart the Mac CoreAudio Daemon
You must use the Terminal to send a “kill” command to the background audio process.
- Open the Finder, go to Applications, open the Utilities folder, and double-click Terminal (or press Command + Space and search for Terminal).
- Carefully type the following exact command into the Terminal window:
sudo killall coreaudiod - Press Enter.
- Because you are using the
sudo(superuser) command to manipulate a core system file, the Terminal will prompt you for your administrator password. Type your Mac login password (the characters will remain invisible) and press Enter again.
The moment you press Enter, the coreaudiod process is instantly terminated. However, macOS is designed with self-healing capabilities. Within milliseconds of detecting the crash, the operating system will automatically restart a brand-new, factory-fresh instance of the audio daemon. Any crackling static will instantly stop, and your volume keys will regain full functionality.