I did try the procedure of toggling the connection to Built-In Audio, which does work fine. When toggling back to the PreSonus the audio connection error message re-appears. The Device Outputs 1 and 2 on the ASIO Playback tab are configured identical to those in WaveLab Pro 9.0; WaveLab Pro 9.0 works fine…WaveLab 8.5.30 on El Capitan does not.