Sorry to bring this up after ~3 years, but I'm stuck on the suggested solution:
I have a similar issue, but when I'm running this:
sudo apt install switchboard-plug-gcc-sound
I get this:
The following packages have unmet dependencies: switchboard-plug-gcc-sound : Depends: unity-control-center but it is not going to be installed E: Unable to correct problems, you have held broken packages.
The above iterates for all the "unmet dependencies".
Any clue about what I might be missing here, would be much appreciated!
Thank you in advance!