CoreAudio/AudioServerPlugIn.h says that .driver plugin packages must be installed in /Library/Audio/Plug-Ins/HAL/
However I don't know of any documentation that tells of how to make CoreAudio notice the appearance of the new driver (or when uninstalling, its absence). Before Catalina [beta 7] most people did something like
sudo killall coreaudiod
and that worked well. However in Catalina, this doesn't work anymore, and the only way I've found to get plugins loaded or unloaded is to reboot the machine, which seems a heavy handed approach for userland plugins.
So is there another way? Or is this a bug?
It looks like coreaudiod is catching SIGTERM and not exiting, so using SIGKILL fixes the problem:
sudo killall -9 coreaudiod
From the unix point of view, not eventually exiting on SIGTERM seems like a bug: FB7244673.
UPDATE I eventually got feedback from Apple that said the only supported method was a reboot. I’ve been ignoring that however.
UPDATE 2024 kickstart -k method was deprecated in Sonoma 14.4 in favour of kill.