Max Gutnik, one of our Pro Tools experts in technical support has the following tip about using the Mackie HUI (Human User Interface): If routing through your MIDI interface, the HUI will think the MIDI port is bad until you connect the HUI's MIDI in and out. If you do the self diagnostic on the HUI, it will tell you that you have a bad midi port unless you take a cable from the MIDI out of the HUI directly into the HUI's MIDI in port.

Editor's note: Every MIDI device I have seen with a self diagnostic routine for checking the MIDI ports understandably requires a MIDI cable to be connected between the MIDI in and MIDI out of the device in order to perform the check accurately.