Under Preferences > Audio/Midi I see no option to enable Audio Units
This is what I should see:
This is what I do see - the option is missing:
System Details:
Garageband 11 version 6.0.5
Mojave 10.14.6
Ultimately I am trying to use a plugin, but I can't get the plugin to show up under my instruments without enabling this option from what I understand
MacBook Pro 15", macOS 10.14
The first screenshot you are showing seems to be from GarageBand 10, not from the older version GarageBand '11, version 6.0.5.
In GarageBand '11 you are adding the audio unit plug-ins from the Info panel in Edit Mode for a track.
The first screenshot you are showing seems to be from GarageBand 10, not from the older version GarageBand '11, version 6.0.5.
In GarageBand '11 you are adding the audio unit plug-ins from the Info panel in Edit Mode for a track.
Audio Units Preference missing garageband 11 - Mojave 10.14.6
