Core Audio is not available in GarageBand: what it means and how to fix it

Core Audio is the part of macOS that handles sound. When GarageBand says it is not available, GarageBand has asked the system for an audio device and not received one it can use.

The wording makes it sound as though something fundamental in macOS has failed. It almost never has. In practice it usually means the input or output device GarageBand was configured to use has gone away, or another application is holding it, or a permission is missing.

That is why the error often appears right after you unplug an interface, wake the Mac from sleep, or install something that adds a virtual audio device.

In GarageBand, open Settings and then Audio or Audio/MIDI. Look at the Input Device and Output Device menus.

If either names something that is not currently connected, an interface you unplugged, a headset that is off, or a virtual device you removed, that is your problem. Set both back to the built-in options and try again.

GarageBand remembers the device per project as well as globally, so an old project can carry a stale setting even when a new one opens fine. If one project throws the error and others do not, this is why.

macOS requires explicit permission for an app to use the microphone, and GarageBand can lose it after a system update or if it was declined once by accident.

Open System Settings, then Privacy and Security, then Microphone, and confirm GarageBand is listed and switched on. If it is not listed at all, quit GarageBand, reopen it and try to record, which should prompt the request.

Toggling the permission off and on again, then restarting GarageBand, resolves cases where the setting looks correct but does not work.

Some applications take exclusive control of an audio device. If a video call, a streaming tool, another DAW or a screen recorder is running, GarageBand may find the device unavailable even though everything is plugged in.

Quit anything that touches audio, including apps that are only sitting in the menu bar, and try again. Video conferencing tools are the usual offenders because they keep the microphone reserved after a call ends.

If that does not clear it, restarting Core Audio itself is the next step. Open Audio MIDI Setup, or restart the Mac, which achieves the same thing with less to explain.

If your input and output devices are set to different sample rates, or a project was created at a rate the current device does not support, GarageBand can fail to open the audio path and report this error.

Open Audio MIDI Setup from Applications and then Utilities, select each device in turn, and check the Format field. Set both to the same rate, 44,100 Hz or 48,000 Hz, then reopen GarageBand.

This is also worth checking if you have built a Multi-Output Device for system-audio capture, because those are easy to leave at a rate that nothing else is using.

If you are hitting this repeatedly and the project is a podcast rather than music, a browser recorder sidesteps device configuration entirely, since it uses whatever the browser already has permission to use. Hilite is one of those and we make it, so weigh that accordingly.