Same issue here since installing updates and new packages for KDE. Kwin wouldn't load at first, this was easily fixed by creating a symlink from /usr/bin/kwin to /usr/bin/kwin_x11
System settings works but shows only a few icons. packes installed and updated to create the issue: Install: libkf5waylandclient5:amd64 (5.3.2-1, automatic) qml-module-qtgraphicaleffects:amd64 (5.4.2-2, automatic) libkwinxrenderutils6:amd64 (5.3.2-2, automatic) kwin-x11:amd64 (5.3.2-2, automatic) qml-module-qtquick-layouts:amd64 (5.4.2-2, automatic) libxcb-cursor0:amd64 (0.1.1-3, automatic) qml-module-qtquick-window2:amd64 (5.4.2-4, automatic) libkwineffects6:amd64 (5.3.2-2, automatic) qml-module-qtquick2:amd64 (5.4.2-4, automatic) libkdecorations2private5:amd64 (5.3.2-1, automatic) libqt5multimedia5:amd64 (5.4.2-2, automatic) libkf5activities5:amd64 (5.12.0-2, automatic) libkwin4-effect-builtins1:amd64 (5.3.2-2, automatic) libkdecorations2-5:amd64 (5.3.2-1, automatic) qml-module-qtmultimedia:amd64 (5.4.2-2, automatic) libqt5multimediaquick-p5:amd64 (5.4.2-2, automatic) qml-module-qtquick-controls:amd64 (5.4.2-2, automatic) libkf5waylandserver5:amd64 (5.3.2-1, automatic) kwin-data:amd64 (5.3.2-2, automatic) qml-module-org-kde-kquickcontrols:amd64 (5.12.0-2, automatic) kwin-common:amd64 (5.3.2-2, automatic) plasma-framework:amd64 (5.12.0-1, automatic) libkf5plasma5:amd64 (5.12.0-1, automatic) libkwinglutils6:amd64 (5.3.2-2, automatic) libkf5plasmaquick5:amd64 (5.12.0-1, automatic) qml-module-org-kde-kquickcontrolsaddons:amd64 (5.12.0-2, automatic) libinput10:amd64 (0.17.0-1, automatic) Upgrade: libunwind8:amd64 (1.1-3.2, 1.1-4) libasan1:amd64 (4.9.3-2, 4.9.3-3) libqt5opengl5:amd64 (5.4.2+dfsg-4, 5.4.2+dfsg-5) libqt5sql5:amd64 (5.4.2+dfsg-4, 5.4.2+dfsg-5) libqt5qml5:amd64 (5.4.2-3, 5.4.2-4) libqt5core5a:amd64 (5.4.2+dfsg-4, 5.4.2+dfsg-5) kde-window-manager:amd64 (4.11.13-2, 5.3.2-2) libqt5xml5:amd64 (5.4.2+dfsg-4, 5.4.2+dfsg-5) xserver-xorg-video-qxl:amd64 (0.1.4-1, 0.1.4-3) libqt5quick5:amd64 (5.4.2-3, 5.4.2-4) libqt5sql5-psql:amd64 (5.4.2+dfsg-4, 5.4.2+dfsg-5) libqt5test5:amd64 (5.4.2+dfsg-4, 5.4.2+dfsg-5) libqt5printsupport5:amd64 (5.4.2+dfsg-4, 5.4.2+dfsg-5) libqt5widgets5:amd64 (5.4.2+dfsg-4, 5.4.2+dfsg-5) libqt5dbus5:amd64 (5.4.2+dfsg-4, 5.4.2+dfsg-5) kscreen:amd64 (5.3.2-2, 5.3.2-4) libqt5gui5:amd64 (5.4.2+dfsg-4, 5.4.2+dfsg-5) libqt5network5:amd64 (5.4.2+dfsg-4, 5.4.2+dfsg-5) ksnapshot:amd64 (4.12.2-2, 15.04.3-1) libdebconfclient0:amd64 (0.194, 0.195) -- Ilan Cohen
