Master volume control is grayed out on my Mac 10.6 (MacBook Pro Late 2009) master volume control for both Line-In built and for external USB Microphone is disabled (grayed out)


Nobody really wanted to help what is the reason and how to bring back such behaviour. Googling didnt provide answer.

What I want is to have master volume slider active at least in Blue Yeti microphone.
Any help?
I ran into issues where my audio controls were disabled similar to what you describe. I can't be sure it's the same issue, but in my case, killing the Core Audio process fixed it.

Open up Terminal and enter this command:

sudo kill -9 `ps ax | grep 'coreaudio[a-z]' | awk '{print $1}'`


You'll be prompted to enter your password, but that should find and kill the proper process, which will then auto-restart. Your volume control should come back to normal within a few seconds if this is indeed the problem.