Rekordbox use disabling sound on PC

So I run sound via a Novation audiohub external interface.  Whenever I use Rekordbox, I can subsequently no longer get sound from anything on the web or itunes.  Ableton still works fine.

The only way I can get sound back to the web/itunes is to unplug and reconnect my soundhub USB.

Is there a rekordbox setting I'm missing that will prevent this behaviour?

It's a new PC running 64 bit windows 10.