The latest Mac OS X 10.11 (El Capitan) compatible TOOLS for MR V1.7.7 show an issue with the audio port names. After changing the "Digital I/O, External FX" setting in the Control Panel, the audio port name is not properly displayed in Cubase or the Audio MIDI Setup.
The audio port name will be displayed properly after restarting the operating system. It could also be that changing the setting repeatedly resolves the problem. We are investigating this behaviour.