For some reason, there seems to be a problem with the coreaudio driver (ad_coreaudio.mxo). If I am running any MSP patches, there is no signal processing (CPU zero, no signal output). If changing the driver to something else ( e.g. Soundflower), processing works properly.
I already downloaded a version of ad_coreaudio.mxo that was posted here on the forum recently by Andrew, but no luck.