Jef_VA2SS's solution did not work for me.
2 different USB microphones (Philips SpeechMike III and Buddy 6 external sound card with Sennheiser ME3 microphone) repeatedly disconnect from VM after establishing connection and using for a few minutes. I am using them with Dragon Professional Individual. DPI works perfectly in VM with no microphone connected i.e. with onboard soundcard for the MacBook. I have tried connecting to Mac, and directly to VM. Tried every setting, searched forums for over 2 weeks, but problem continues. Rolling back to 17.0.1 did not resolve. There appears to be a major USB issue with 17.1.0, 17.1.1 and 17.1.2 (all of these versions lead to my USB microphones being disconnected randomly).