[SOLVED] appear qmail login ubuntu 12.04

source : http://askubuntu.com/questions/2471/how-to-hide-users-from-the-gdm-login-screen How to hide users from the GDM login screen? | I have recently added several new users, that I need for qmail. Now they appear in the box in the login screen and clutter it, and I have to scroll to find my user. How can I hide those users from the login box? alias qmaild qmaill qmailp qmailq qmailr qmails so many user login appear in login screen although i have deleted the gdm (apt-get remove qmail || apt-get purge gdm) make me confuse, then i try to delete it using this comment sudo usermod -u 999 <username> example : sudo usermod -u 999 qmaild sudo usermod -u 998 qmaill etc then restart the system by typing : restart lightdm