Restoring a Missing Date and Time Indicator
The little date and time indicator vanished from the top panel of the screen. This is what I did to get it back.
I made sure all elements of it were still installed (in case anything had borked any of the required files).
sudo apt-get install indicator-datetime
I issued the following command to reconfigure the date and time timezone data through dpkg.
sudo dpkg-reconfigure –frontend noninteractive tzdata
Finally I restarted Unity.
sudo killall unity-panel-service
That was it. Short and sweet.