KDE/Troubleshooting

This article contains various sections to help KDE users troubleshoot their systems.

Open GUI programs as root
KDE Plasma, along with other desktop environments, include a special command in order to start graphical programs with root privileges. For Plasma the command is. It can be used in the following manner:

Be sure to substitute  in the command above with the name of the program. A pop-up window should be displayed containing a text box for the root password. Enter the password and boom: happiness.

Rebuilding the application database
If the KMenu lacks any application or the whole application list, the KDE application database probably needs to be rebuilt. This is also a possible fix for any KMenu related issues, like missing icons.

Akonadi complains about the MySQL config
Start by checking the permissions in. If they're 700, update them to 755 recursively.

If that doesn't solve the error, open the akonadi configuration and change the default MySQL config. If the tray is not running, start, select "Akonadi Server Configuration", activate "Use internal MySQL server" and then press the test button. To use the MySQL server and not the embedded executable, make sure that MySQL is running.

Unable to mount devices using KDE Plasma Device Notifier
If the error message "You are not authorized to mount this device." is being displayed when trying to mount devices by clicking them in the KDE Plasma Device Notifier (USB-stick-like icon in the system tray), add the following file to your configurationː

This will allow all users who are members of the plugdev group to mount devices using the Device Notifier.

Use the following command to add users to this groupː

Black screen after login
Make sure ~/.bash_profile does not have any interactive components like keychain. Check ~/.xsession-errors for the prompt for input.

Screen Tearing/Flicker when using Radeon graphics drivers
If there is severe flickering or "tearing" when using Radeon based graphics cards, it may be necessary to change the Compositor sync settings to something other than the default "Automatic":

System Settings --> Display Monitor --> Compositor --> VSync

Delayed response of KMenu, krunner etc.
Remove  USE flag and rebuild affected packages, most importantly in ,  and.

Missing shutdown/reboot/suspend/hibernate buttons (with consolekit)
Make sure that and  are installed. Also check that the user is in the group.

If is used, run the following command and make sure it matches the output including  :

Another option is to create the following polkit rule for suspend :

Also ensure dbus is added to the default runlevel so that it is started before logging in with sddm:

If all else fails, try instead.