SUMMARY STEPS TO REPRODUCE 1. start kontact 2. 3. OBSERVED RESULT app starts but hangs/freezes and is unusable. The single apps like kmail/korganizer could be started separately and are working flawlessly. Journalctl says: Jun 08 21:10:21 munin akonadiserver[1296]: org.kde.pim.akonadiserver: New notification connection (registered as Akonadi::Server::NotificationSubscriber(0xffff88299820) ) Jun 08 21:10:21 munin akonadiserver[1296]: org.kde.pim.akonadiserver: Subscriber "" disconnected Jun 08 21:10:21 munin akonadiserver[1296]: org.kde.pim.akonadiserver: New notification connection (registered as Akonadi::Server::NotificationSubscriber(0xffff881c3c90) ) Jun 08 21:10:21 munin akonadiserver[1296]: org.kde.pim.akonadiserver: New notification connection (registered as Akonadi::Server::NotificationSubscriber(0xffff881c3c90) ) Jun 08 21:10:21 munin akonadiserver[1296]: org.kde.pim.akonadiserver: New notification connection (registered as Akonadi::Server::NotificationSubscriber(0xffff88127bc0) ) Jun 08 21:10:21 munin akonadiserver[1296]: org.kde.pim.akonadiserver: New notification connection (registered as Akonadi::Server::NotificationSubscriber(0xffff882d7b20) ) Jun 08 21:10:21 munin akonadiserver[1296]: org.kde.pim.akonadiserver: New notification connection (registered as Akonadi::Server::NotificationSubscriber(0xffff88299b30) ) Jun 08 21:10:21 munin kernel: Purging 8388608 bytes Jun 08 21:10:22 munin akonadiserver[1296]: org.kde.pim.akonadiserver: Subscriber Akonadi::Server::NotificationSubscriber(0xffff88299820) identified as "TagCacheMonitor - 187650858043648" Jun 08 21:10:22 munin akonadiserver[1296]: org.kde.pim.akonadiserver: Subscriber Akonadi::Server::NotificationSubscriber(0xffff881c3c90) identified as "ETMCalendarMonitor - 187650858330464" Jun 08 21:10:22 munin akonadiserver[1296]: org.kde.pim.akonadiserver: Subscriber Akonadi::Server::NotificationSubscriber(0xffff88127bc0) identified as "TagCacheMonitor - 187650858682448" Jun 08 21:10:22 munin akonadiserver[1296]: org.kde.pim.akonadiserver: Subscriber Akonadi::Server::NotificationSubscriber(0xffff882d7b20) identified as "ItemMonitorMonitor - 187650859137952" Jun 08 21:10:22 munin akonadiserver[1296]: org.kde.pim.akonadiserver: Subscriber Akonadi::Server::NotificationSubscriber(0xffff88299b30) identified as "TagCacheMonitor - 187650859766896" Jun 08 21:10:22 munin kwin_x11[1164]: qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 21563, resource id: 37763433, major code: 3 (GetWindowAttributes), minor code: 0 Jun 08 21:10:22 munin kwin_x11[1164]: qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 21887, resource id: 165675019, major code: 18 (ChangeProperty), minor code: 0 Jun 08 21:10:23 munin kded5[1122]: Registering ":1.131/StatusNotifierItem" to system tray Jun 08 21:10:23 munin plasmashell[1166]: QQuickItem::stackAfter: Cannot stack StatusNotifierItem_QMLTYPE_382(0xaaaaf415dd60, parent=0xaaaaf2c54820, geometry=0,0 0x0) after StatusNotifierItem_QMLTYPE_382(0xaaaaf36caab0), which must be a sibling Jun 08 21:10:23 munin kwin_x11[1164]: qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 22069, resource id: 165675019, major code: 18 (ChangeProperty), minor code: 0 Any tips for me? EXPECTED RESULT SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: (available in About System) KDE Plasma Version: KDE Frameworks Version: Qt Version: ADDITIONAL INFORMATION