[Curtis Allen]

I had the same problem, until today.

My Shure X2u worked fine with other mics
My Coles Lip Mic worked fine plugged into my camera
But combining the two together resulted in no audio, no VU meter activity.

I tried it in FCP, Quicktime, and Audacity, all using “Shure” as the source, but getting nothing.

The fix though was going into Preferences -> Sound and making sure Shure Digital was selected. All of a sudden it started working.

I went into Audacity and recorded and it was working.

Hope this helps