After installing macOS Mojave, when trying to record you might see an alert that says audio input isn't accessible. Or you might not hear sound, see waveforms, or see audio meters move when recording. To record audio, allow the app to access audio inputs:
- Close the app you're using to record audio.
- On your Mac, choose Apple menu () > System Preferences, click Security & Privacy, then click Privacy.
- Click Microphone.
- Select the checkbox next to an app to allow it to access the built-in microphone on you Mac, an external USB mic, or the inputs on an external audio interface.
- Open the app and try to record audio again. If you're using a USB mic or an external audio device and you still can't record audio, check with the manufacturer for software updates and information on compatibility.