A recent Windows 10 update (June 2018) has been known to change the privacy settings in Windows 10 in some cases, resulting in a connected microphone to cease functioning. In other words, the microphone you may be using with Dragon Professional may “not work” any longer.
This is a very easy fix and can be performed as follows:
Click on your Windows icon (usually found at the lower left corner of your desktop on the taskbar). Then click on Settings (pictured as a gear). Click on Privacy. On the Privacy Settings menu on the left-hand side, click Microphone. Ensure that “Let apps use my microphone” is set to On.
And that’s it!