Master volume control is grayed out

Solution 1:

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.

Solution 2:

With some digital audio input devices, by design, it is not possible to adjust the volume level within System Preferences, Audio MIDI Setup, or GarageBand or the like. The volume level can only be adjusted on the external digital audio device.

I suggest that you contact the technical support staff at Blue Microphones, the company that makes your microphone, to ask them about this.

Solution 3:

You could check System Preferences > Sound > Input and make sure it is set to the correct audio device.

Without more information it's difficult to offer much more advice than that.