Monterey Bluetooth bug

macOS Monterey 12.0-12.3 shipped with a Bluetooth bug that caused all output to be muted whenever a Bluetooth device’s microphone is muted.

Apple fixed this bug in 12.4. We encourage all users to upgrade to macOS Monterey 12.4 or newer you so you can use Bluetooth microphones with no issues.

If you are using macOS 12.0-12.3, Mic Drop will use a workaround that forces the Bluetooth microphone to be unused and will use your Mac’s built-in microphone instead.

Why does my audio mute when I mute my microphone on a Bluetooth device?

This was a bug in macOS Monterey until version 12.4. Bluetooth input and output were (incorrectly) linked in these versions of Monterey, so anytime your Bluetooth mic was muted, the audio would cut out. It happened with any app that mutes the mic, although it only impacts Bluetooth headphones.

How can I fix it?

The best way to fix it is to upgrade your Mac to macOS 12.4 or newer.

How does the workaround work?

If you’re using macOS Monterey before version 12.4, when Mic Drop detects you’re using a Bluetooth mic as your microphone, it automatically switches your Mac’s microphone to a non-Bluetooth mic. In many cases, this will be your Mac’s built-in microphone or your webcam.

Whenever you mute using Mic Drop, we mute all inputs except Bluetooth devices. This stops your Bluetooth headphones from being muted, but it also means you can’t use the mic built in to your Bluetooth headphones.

Fortunately, most Macs have a reliable built-in mic, so this approach works well. Mic Drop will select the first non-Bluetooth mic it finds, but you can change the input in System Preferences > Input.

Matt wrote a whole blog post on how we implemented our Monterey Bluetooth workaround.

Make sure other apps aren’t using Bluetooth input

Some apps may try to use a different microphone to your system settings, which means they’ll collect audio from a microphone that isn’t muted. We can’t control or predict this, but we do try to prevent other apps from using the input of Bluetooth microphones by disabling other app’s access to Bluetooth mics when Mic Drop is running.

Built-in microphones and clamshell mode

Recent MacBooks (since about 2018), including all M1 MacBooks, have a physical disconnect for the built-in microphone when the lid is closed. This is to prevent sleeping devices from listening to you, but it means you can’t use the built-in microphone in clamshell mode.

Mic Drop will ignore the built-in microphone in clamshell mode when using Bluetooth headphones, instead trying to use another mic (like the one built into your webcam). If no mutable microphones are available in clamshell mode, we’ll let you know with a “Mute Error” notification.