Printer Add button not enabled in ubuntu 12.04

When CUPS is not running the Printers panel looks like this on my Ubunbu 12.04:

Is this what you see?

About CUPS:

• Use this command to check whether CUPS is installed:

  dpkg --list | grep ' cups '
  

  Typical output when installed is:

  ii  cups                1.5.3-0ubuntu4      Common UNIX Printing System(tm) - server
  

  If you don't see any output, install CUPS:

  sudo apt-get install cups
  

  and start it:

  Ubuntu 12.04: sudo service cups start

  Ubuntu 16.04: sudo sudo systemctl start cups.service

• If it is already installed it may not be running, check it like this:

  ps -ef|grep cups | grep -v grep
  

  Typical output when running is:

  root       925     1  0 Oct17 ?        00:00:00 /usr/sbin/cupsd -F
  

  If you don't see any output CUPS is not running. Start it like this:

  Ubuntu 12.04: sudo service cups start

  Ubuntu 16.04: sudo sudo systemctl start cups.service

Could you try it and post any problems?

More information on CUPS:

• Ubuntu 12.04: https://help.ubuntu.com/12.04/serverguide/cups.html

• Ubuntu 16.04: https://help.ubuntu.com/16.04/serverguide/cups.html