If you have Mac Mojave OS, you may not be able to use your microphone in Zoom. If this happens to you, you will need to modify your security and privacy preferences

To modify these settings:

  1. Go into your security and privacy preferences.
  2. Select to allow Zoom to access the microphone.
  3. Restart Zoom.

Here is a screenshot of the Security & Privacy screen from a Mac OS Mojave machine (sent to us by an instructor):