This article contains various sections to help users of KDE software troubleshoot their systems.
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 /usr/share/config. If they're 700, update them to 755 recursively.
chmod -R 755 /usr/share/config
If that doesn't solve the error, open the akonadi configuration in ~/.config/akonadi/akonadiserverrc and change the default MySQL config. To use a MySQL server and not the local mysqld executable, make sure that MySQL is running.
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 or flickering 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.
Packages from the
dev-qt category provide a
gles2-only USE flag which in the past has caused this effect. It is not advised to enable it. If for no good reason this flag is found to be enabled for
dev-qt, kde-frameworks/plasma or kde-plasma/kwin, then remove all occurrences of this flag and rebuild affected packages.
Missing features like these are often symptoms of not using kde-plasma/plasma-meta. It only provides the desktop and is highly configurable with USE flags. Use it.
KDE Plasma high CPU usage
If you are noticing relatively high CPU usage (normally the dbus-daemon or kwin_x11 processes) when running KDE Plasma make sure to check the syslog for errors that look like the following. Normally just tailing the log will enable you to see this right away since the error is thrown at such a high rate.
... Oct 17 00:30:26 localhost obexd: obex_server_init failed Oct 17 00:30:26 localhost obexd: OBEX daemon 5.39 Oct 17 00:30:26 localhost obexd: obex_server_init failed Oct 17 00:30:26 localhost obexd: OBEX daemon 5.39
This occurs due to being unable to connect to the bluetooth service you can ensure this is started by running /etc/init.d/bluetooth start on OpenRC systems. To ensure this does not happen on any other start run the following.
rc-update add bluetooth
Alternatively bluetooth can be disabled from via the GUI.
System Settings --> Bluetooth --> Advanced Settings --> Enable Bluetooth integration
dev-qt/qtwebkit is one of the few packages known to consistently fail when the
j value on MAKEOPTS is set too high.
If you see mysterious build failure, try lowering your
j value. The safe value would be the number of processor times thread (not that plus one).
Similar case has been found when compiling with j option while KDE Plasma is running (observed with dev-qt/qtwebkit and dev-qt/qtwebengine). The build failure would be accompanied with desktop program lagging (or crashing). If this happen, you might want to consider compiling under TTY.
In other case when you see out-of-memory failure, you may want to get rid of pipe on CFLAGS.
Plasma Browser Integration not working in Firefox
Device permissions issues and missing shutdown/reboot options
Missing suspend or hibernate options
Beyond that, suspend and hibernate options depend on that support being enabled in the kernel, see also: Suspend and Hibernate