Step 1: Open Terminal ( Dash Home —-> Search for Terminal or Ctrl + Alt + T)
Step 2: Edit the /etc/lightdm/lightdm.conf file.
raj@geeksite~$ sudo vi /etc/lightdm/lightdm.conf
Step 3: Add the following line at the end of the above file.
greeter-hide-users=true
Step 4: Reboot
raj@geeksite~$ sudo reboot
Now the login scree will look like below without User Names list except Guest Session.
That’s all.
**warning** this deletes all ability to access user accounts on 14.04.
If this happens to you then use ctrl + alt + F2 from the login screen to get the terminal and use it to undo Step 3. After you sudo reboot your computer should be back to normal.