For UNIX® operating systems there are often different users, which in turn might have different privileges. The conventional method is to have an ordinary user account, whose files are generally stored in /home/username, and then to also have a root account. The root, or Super User, account has system-wide privileges, being able to modify any file on the system.

Although this means that it is easy to perform administrative tasks without hassle, it also means that there are no security restrictions imposed upon it. Thus, a small typographical error or other mistake can result in irrevocable damage.

Some of the operating systems that run KDE come with a graphical root login enabled. Despite this, you should never log in to KDE as root, and you should never need to. Your system is far more open to attack, particularly if you are browsing the Internet as root, and you dramatically increase your chances of damaging your system.

Some Linux® distributions have tried to stress this point so much that they have disabled the root account altogether, and instead use the sudo model. Nevertheless, the basic security model in sudo is the same as su, and thus they share the same security strengths and weaknesses, essentially.

If you should ever need to run a program with Super User privileges, then it is always recommend that you use KDE su. From Konsole or from hitting Alt+F2, enter kdesu application, and the application will be run with the appropriate Super User privileges.

Even if you have set up your system to use sudo, or you are on a distribution that uses sudo, such as Kubuntu™, you should still use KDE su. The program will be appropriately modified by the developers to use the correct settings. You should not, however, ever use sudo application to run an application with root permissions; it can derange permissions of certain configuration files for a program. Running a graphical applications as root in general is not a good idea, but using KDE su will always be your safest bet with it.