Cannot hear thru headphones with USB mic plugged in

Audacity 3.1.3
Windows 10 Home or OS X 10.5.8).
USB mic plugged into USB port.
Headphones plugged into headphone jack.
Recording works fine. Playback will not come thru the headphones unless I unplug the USB mic. When I plug the mic back in playback cannot be heard again thru the headphones.
I’ve googled and searched and messed with all kinds of settings but cannot seem the fix the issue.

So each time you change your USB connections you need to do Transport > Rescan Audio Devices. :smiley:

But I want to be able to hear playback in my headphones without unplugging my mic. Transport/rescan does nit accomplish this.

Are they specified as the Playback Device in your Device Toolbar ?