GarageBand: "Error code -2 was returned by the CoreAudio driver"
When you open GarageBand, you may receive this alert message:
"Error code -2 was returned by the CoreAudio driver."
If you click the Continue button, the audio in the project will not play.
This issue affects GarageBand 3.0.2 or later.
To resolve the issue:
Click the Continue button to dismiss the alert message.
From the GarageBand application menu, choose Preferences.
Select the Audio/MIDI pane.
Set the Audio Input and Audio Output menus to the correct audio interface. For most users, this will be Built-in Audio.
Close the Preferences window.