Ubuntu 12.04 sound applet missing but sound working

Some times it happens while making some update to some other User interface like Cinnamon.

Sound applet or icon from the right top panel of ubuntu 11.04/12.04/12.10 doesn’t appear but sound still keep on working.

This way we can add sound applet again to the panel:

1. Open Terminal and write these commands one by one:

2.  Install missing Sound indicator applet :

   sudo apt-get install indicator-sound 

3. Refresh Unity using this command:

   killall unity-panel-service