1. What is the model of your microphone?
Please go to the manufacturer's website and download/install the proper audio driver, and try it again.
2. Do you have the problem with the AAC codec?
Please choose "MPEG-1" or "PCM" audio codec, and try it again.
3. What is your Bandicam version?
You've been using Bandicam for over 9 months.
Didn't you have the microphone issue with old versions of Bandicam?