Unfortunately, it has come to our attention that the drivers from DisplayLink which control the USB adapter availbale through our Store, as well as, most USB Display adapters on the market, are currently causing incompatibility with Mac OS 10.12.4
They've listed this information on their website here, http://support.displaylink.com/knowledgebase/articles/949426 and the main issue we're seeing is related to this in their list, "Since 10.12.4, some systems show corrupted window contents in some applications (Word, Keynote, Parallels, LVC for example). (31495935)"
We have had a few issues reported such as slow downs in the program itself, as well as, outputs not working as expected through the USB adapter. From what we've seen so far, this has mostly affected those using the Live Slide causing a static look on the Stage Display, but other issues have been reported as well.
At this time, the only recommendations/work-arounds we have is to either not update to OS 10.12.4 until this is rectified or you will need to find a separate output on the computer to send your Stage Display output through. We apologize for the inconvenience, but unfortunately, this issue is out of our hands.