Ubuntu 14.04, 16.04 and 17.04 Unity, Dash and Launcher missing

If you end up missing the menu etc in Ubuntu 14.04, 16.04 and 17.04, i.e. you only see the desktop but nothing more. You can’t even restart the machine.

It can be resolved like this:

• Right click on the desktop and select “Start a new terminal”
• In the terminal window run the following commands;
  sudo apt-get update
sudo apt-get install --reinstall ubuntu-desktop
sudo apt-get install --reinstall unity
sudo shutdown -r now