Desfaça o dano executando
apt-get remove --auto-remove qml-module-org-kde-kio kde-telepathy-minimal liboxygenstyle5-5 k3b-data kimageformat-plugins libgpgme++2 kde-style-breeze-qt4 kdenetwork-filesharing libkblog4 plasma-widgets-addons libqt5concurrent5 libkimap4 ttf-oxygen-font-family gtk3-engines-oxygen freerdp-x11 libk3b6-extracodecs user-manager libktpwidgetsprivate8 libksieve4 gpgsm kwalletmanager kde-telepathy-call-ui libqtgstreamerui-1.0-0 frameworkintegration libktpotrprivate8 mysql-server-core-5.6 kwrited libakonadi-kcal4 kdepim-kresources libkf5style5 ark kmail libkf5waylandclient5 libokularcore6 plymouth-theme-kubuntu-logo ksysguard libqt4-sql-mysql libmailtransport4 libkf5unitconversion5 kde-telepathy-filetransfer-handler breeze-cursor-theme akonadi-backend-mysql kde-config-gtk-style-preview libkpimtextedit4 mysql-client-core-5.6 liblastfm1 libtag-extras1 kdepimlibs-kio-plugins libkpeople4 libqrencode3 libakonadiprotocolinternals1 libbalooxapian4 akonadi-server kubuntu-notification-helper kdemultimedia-kio-plugins cdparanoia libplasma-geolocation-interface5 libmessagecomposer4 libweather-ion7 cdrdao libibus-qt1 bluedevil kdeconnect libbalooqueryparser4 libzip2 libkwinxrenderutils6 libakonadi-notes4 kwin-style-breeze orion-gtk-theme libktpmodelsprivate8 kde-cli-tools libksieveui4 muon-discover libkfontinst5 libeventviews4 libkf5emoticons5 libkf5texteditor5 libmicroblog4 libkf5wallet5 libkcddb4 amarok-utils kded5 libmailcommon4 libktpcommoninternalsprivate8 libmusicbrainz5-1 sddm-theme-breeze libkf5networkmanagerqt6 libkdepim4 libpowerdevilcore2 kaddressbook libreoffice-style-breeze soprano-daemon libkf5krosscore5 libmessageviewer4 libsoprano4 vcdimager libcln6 kde-style-breeze libbaloopim4 okular libkf5threadweaver5 libqca2-plugin-ossl plasma-runners-addons libqtgstreamer-1.0-0 ubuntu-release-upgrader-qt python3-pyqt4 python3-pyqt5 sshfs kde-config-touchpad muon-common libkf5su-bin kdesudo libkf5xmlrpcclientprivate5 libxerces-c3.1 kde-telepathy-data kcalc libkf5screen6 libkf5filemetadata-data libkworkspace5-5 libqmobipocket1 systemsettings ktexteditor-katepart gstreamer-qapt libkolabxml1 libsyndication4 libotr5 libksane0 libkf5khtml5 libkprintutils4 libmuon libtaskmanager5 knotes scdaemon libincidenceeditorsng4 libkf5balooxapian1 libkf5jsembed5 qml-module-org-kde-kcoreaddons libk3b6 amarok kde-telepathy-contact-list kubuntu-desktop gwenview libcalendarsupport4 libkcalcore4 baloo-kf5 libkmbox4 libkwineffects6 libakonadi-contact4 libakonadi-socialutils4 plasma-widget-kimpanel muon-notifier libkf5js5 libpowerdevilui5 ksshaskpass qtdeclarative5-kf5solid libpoppler-qt5-1 libkholidays4 libtelepathy-qt5-0 libkf5prison1 qml-module-org-kde-draganddrop libqtscript4-gui kde-telepathy-legacy-presence-applet libkf5filemetadata-bin qt5-image-formats-plugins python3-pykde4 qml-module-org-kde-solid breeze libao-common libxcb-record0 libtomcrypt0 kio-extras-data libkcompactdisc4 kde-config-telepathy-accounts debconf-kde-data kio-audiocd libkabc4 okular-extra-backends kde-telepathy-auth-handler liboxygenstyleconfig5-5 plymouth-theme-kubuntu-text libkdecorations2private5 qdbus-qt5 libqimageblitz4 libkf5webkit5 libjs-prototype ktorrent-data kde-config-tablet libkf5newstuff5 libqt5designercomponents5 libbaloowidgets4 kmenuedit akregator python3-dbus.mainloop.pyqt5 libxcb-xtest0 kate libkf5emoticons-data libkresources4 libkwalletbackend5-5 libkmanagesieve4 qtgstreamer-declarative kde-config-sddm libkf5emoticons-bin qttools5-dev-tools kde-telepathy-kpeople libqtscript4-network libksane-data ibus-qt4 libkwin4-effect-builtins1 plasma-nm apturl-kde libqgpgme1 print-manager qml-module-org-kde-extensionplugin libksignalplotter5 plasma-desktop-data libtelepathy-qt4-farstream2 libkipi-data libkdecorations2-5 libakonadi-kmime4 gtk2-engines-oxygen libkf5kiontlm5 libfollowupreminder4 korganizer libkf5sysguard5 kde-telepathy-text-ui libkcal4 libkmime4 ksysguardd kontact libmailimporter4 libakonadi-calendar4 libprison0 libsendlater4 libsignon-qt1 libkf5khtml-bin libprocesscore5 libkldap4 libqca-qt5-2-plugins libqt5quickwidgets5 kubuntu-settings-desktop kde-telepathy-approver kamera libbaloofiles4 libtelepathy-qt4-2 libfakekey0 libnoteshared4 qml-module-qtmultimedia libakonadi-kde4 libreoffice-kde libjs-scriptaculous libkf5baloo1 libscim8c2a oxygen-sounds libqt5multimediawidgets5 mysql-common libkf5itemmodels5 libgrantlee-gui0 socat libkdepimdbusinterfaces4 libboost-thread1.55.0 libkf5krossui5 apport-kde libkf5khtml-data qtdeclarative5-kf5declarative kio-mtp ksystemlog libqt5multimediaquick-p5 libkfontinstui5 liboath0 sddm libmessagecore4 libqtglib-2.0-0 libstoken1 libkf5su5 qml-module-qtquick-controls kubuntu-driver-manager libmygpo-qt1 libknewstuff2-4 dragonplayer libmysqlclient18 libgps21 kde-telepathy-send-file khelpcenter libkidletime4 qapt-deb-installer breeze-icon-theme plasma-dataengines-addons libfreerdp-rail1.1 libkf5wallet-bin libtemplateparser4 about-distro dolphin libbluedevil1 polkit-kde-agent-1 kinfocenter amarok-common libkf5waylandserver5 kwin-data libqtscript4-uitools libxcb-composite0 qml-module-org-kde-kquickcontrols libkcalutils4 libbaloocore4 powerdevil-data kwin-addons plasma-desktop skanlite kdegraphics-strigi-analyzer libdmtx0a libprocessui5 plasma-framework libtommath0 libperl4-corelibs-perl qml-module-qtquick-controls-styles-breeze libloudmouth1-0 libktnef4 libkf5newstuff-data kde-style-oxygen-qt5 libkf5plasma5 libflac++6 libkf5filemetadata3 libkf5dnssd5 libkleo4 pam-kwallet libqalculate5-data libkf5jsembed-data libopenconnect3 software-properties-kde libkwinglutils6 ktorrent libqca-qt5-2 libkf5sysguard5-data krdc libksgrd5 milou libqtscript4-core partitionmanager kdeplasma-addons-data powerdevil kscreen libkf5runner5 ktexteditor-data libkf5plasmaquick5 libkfbapi1 libxcb-damage0 kde-cli-tools-data kdeconnect-plasma plasma-wallpapers-addons libkpimidentities4 konversation-data libreoffice-style-oxygen k3b libkipi11 phonon4qt5-backend-gstreamer libqt5multimedia5-plugins libao4 libkfilemetadata4 libdebconf-kde1 libktorrent-l10n libkolab0 libepub0 libkdgantt2-0 plasma-workspace qml-module-org-kde-runnermodel libqgsttools-p1 libqtscript4-xml kubuntu-web-shortcuts libtelepathy-logger-qt4-1 libkpimutils4 kate5-data khotkeys pinentry-qt4 kde-config-gtk-style khotkeys-data libkalarmcal2 kross libkgapi2-2 libkubuntu1 python3-sip kmix kio libqalculate5 baloo-utils ksnapshot libktorrent5 libakonadi-kabc4 konversation kwin libpimcommon4 libktploggerprivate8 kde-config-whoopsie qml-module-org-kde-kquickcontrolsaddons libkpgp4 libkf5modemmanagerqt6 kio-extras libkexiv2-data libkf5dnssd-data muon-updater kde-telepathy kde-telepathy-declarative libaccounts-qt1 libkf5unitconversion-data libqtscript4-sql ksysguard-data libkexiv2-11 libkontactinterface4 libmessagelist4 kinit kde-telepathy-integration-module libgrantlee-core0 libkf5idletime5 libxfreerdp-client1.1 kdepim-runtime
(todos os pacotes que foram instalados com o kubuntu para mim podem ser diferentes para você).
Você pode encontrar os pacotes a serem removidos neste arquivo:
/var/log/apt/history.log
depois da linha
Commandline: apt-get install kubuntu-desktop
Detalhes aqui .