Starting with Fedora 10 (and continuing with Fedora 11 and Fedora 13), graphical root login was disabled by default. Allowing root login to the GUI poses a number of security risks, so doing so is not recommended. In most cases, using sudo or simply authenticating as the superuser in the graphical interface when an application asks for will work. However, for those rare cases where logging in as root in the graphical interface is needed, here’s how to do it:
Step 1: Edit /etc/pam.d/gdm
Use your favorite text editor to open /etc/pam.d/gdm and comment out the following line (by placing a # in front of it):
auth required pam_succeed_if.so user != root quiet
Step 2: Edit /etc/pam.d/gdm-password
Now open /etc/pam.d/gdm-password and comment out this line:
auth required pam_succeed_if.so user != root quiet
Once those lines are commented out of both files, you should be able to login as root in the GUI. You’ll receive a warning when you do so which explain that there are security risks associated with graphical root login. Please proceed with caution and use only when necessary. You could hose your system big time if you mess something up. Good luck!