As long as you don’t actually have any audio input device connected, such as an external microphone or some other line-in device, this method is very effective. This works by changing the audio input to the line-in, also known as the audio input port on your Mac. This is not an option in newer versions, however, newer Macs can always just plug in a different line-in source and then select that and reduce the volume as described above. On older versions of Mac OS X you can also just select a different audio input like line-in, even if another mic is not connected to the Mac. How to Disable the Internal Microphone on Mac by Selecting a Different Audio Input If you want to basically disable the internal microphone’s ability to hear audio entirely, use the below method instead. This control panel for the Microphone looks a little different depending on the version of Mac OS X used on the Mac, but it always allows users to change the microphone input level to zero thereby disabling the ability to pick up sound. This method works to turn off the microphone by reducing the audio input to zero, effectively making the internal microphone unable to capture any sound. Drag the “Input volume” slider all the way to the left, as seen in the included screenshot – you can test the microphone has been disabled by talking and you’ll notice the mic indicator no longer moves.

Launch System Preferences from the  Apple menu in the upper left corner.

How to Disable the Internal Microphone on Mac by Reducing the Input Volume to 0 To disable an external microphone, simply unplug it from the Mac. Note these work to disable the Macs internal built-in microphone in all versions of Mac OS X and with just about every Mac.

Mac internal mic not working