Grayed out "Show volume in menu bar"
The volume icon is no longer visible on the task bar.
When I go to system preferences/sounds the bottom is grayed out, and when I click on 'show volume in menu bar' box it will not check the box (not responding).
The "mute" box is checked but clicking on it to uncheck it doesn't work
iMac 21.5″, macOS 10.15