[RESOLVED] Login screen broken in Plasma 6

[joneall]

Yesterday, I installed the latest updates. I then went to eat dinner. When I got back, the screen was black with a message something like "login screen saver broken" and some instructions about what to do. I was a double idiot because (1) I did not note or photograph the exact message, and (2) I supposed a reboot would fix it. Wrong.

Now when I boot that system, all I get is a black screen. My cursor works on it, but there is nothing to click on. No, I did not think to check with the cursor at screen edge or corners. Fortunately, I have another system -- which I will NOT upgrade until this is fixed.

I remember the message involved using alt-del-F2 and an instruction to run, but alt-del-F2 has absolutely no effect for me. There are a number of folks with similar problems like this or this, but I don't really find a solution among them. Several problems on this forum involve plasma 5, not 6.

Short of reinstalling the system, what can I do now?

[Beerislife]

I booted this morning to a black screen and a mouse cursor in KDE Neon, fully updated!

I needed my PC so installed Mint Cinnamon for the time being!

[joneall]

I booted this morning to a black screen and a mouse cursor in KDE Neon, fully updated!

I needed my PC so installed Mint Cinnamon for the time being!

Was there not accompanying message, as in my case?

[Snowhog]

Everything okay here. Just booted to KDE neon User Edition with no issues:

[Snowhog]

Updating now. Will see how it behaves after a restart.

The following packages were automatically installed and are no longer required:
libclang-cpp14 libclang1-14 libllvm14 libqalculate22
Use 'sudo apt autoremove' to remove them.
The following NEW packages will be installed:
libclang-cpp15 libclang1-15 libqalculate23 linux-headers-6.5.0-27-generic linux-hwe-6.5-headers-6.5.0-27 linux-image-6.5.0-27-generic linux-modules-6.5.0-27-generic linux-modules-extra-6.5.0-27-generic
The following packages have been kept back:
python3-update-manager
The following packages will be upgraded:
breeze breeze-cursor-theme breeze5 bsdextrautils bsdutils distro-release-notifier eject fdisk firefox frameworkintegration fwupd kaccounts5-integration kactivitymanagerd kde-nomodeset kde-style-breeze kde-style-breeze5 kdeconnect kf6-frameworkintegration kf6-kdeclarative
kf6-kguiaddons kf6-ki18n kf6-kiconthemes kf6-kio kf6-kirigami kf6-kirigami-addons kf6-kirigami2 kf6-krunner kf6-kwindowsystem kf6-kxmlgui kf6-qqc2-desktop-style kio-extras kio-extras5 kio-extras5-data kpackagelauncherqml kwayland-integration kwin-common kwin-data
kwin-style-breeze kwin-wayland kwin-x11 layer-shell-qt libblkid1 libfdisk1 libfwupd2 libkcolorpicker-qt6-0 libkf5declarative-data libkf5declarative5 libkf5guiaddons-bin libkf5guiaddons-data libkf5guiaddons5 libkf5i18n-data libkf5i18n5 libkf5iconthemes-bin libkf5iconthemes-data
libkf5iconthemes5 libkf5kirigami2-5 libkf5quickaddons5 libkf5style5 libkf5xmlgui-bin libkf5xmlgui-data libkf5xmlgui5 libkimageannotator-qt6-0 libkpipewire6 libkpipewirerecord6 liblayershellqtinterface6 libmount1 libnspr4 libnss3 libpolkit-qt5-1-1 libqaccessibilityclient-qt6-0
libqalculate-data libqca-qt6-2 libqca-qt6-2-plugins libqcoro6dbus0 libqt5core5a libqt5dbus5 libqt5designer5 libqt5feedback5 libqt5gui5 libqt5help5 libqt5hunspellinputmethod5 libqt5multimedia5 libqt5network5 libqt5positioning5 libqt5printsupport5 libqt5qml5 libqt5qmlmodels5
libqt5qmlworkerscript5 libqt5quick5 libqt5quickcontrols2-5 libqt5quicktemplates2-5 libqt5sql5 libqt5sql5-sqlite libqt5svg5 libqt5test5 libqt5texttospeech5 libqt5virtualkeyboard5 libqt5waylandclient5 libqt5waylandcompositor5 libqt5webchannel5 libqt5webengine-data libqt5webengine5
libqt5webenginecore5 libqt5widgets5 libqt5x11extras5 libqt5xml5 libqt5xmlpatterns5 libqt6core6 libqt6gui6 libqt6sql6-sqlite libsmartcols1 libuuid1 linux-generic-hwe-22.04 linux-headers-generic-hwe-22.04 linux-image-generic-hwe-22.04 linux-libc-dev mount phonon4qt5-backend-vlc
phonon4qt6-backend-vlc plasma-integration plasma-integration5 plasma-workspace plasma-workspace-wayland python3-pyqt5 qml-module-org-kde-kcm qml-module-org-kde-kirigami2 qml-module-org-kde-kquickcontrolsaddons qml-module-org-kde-qqc2desktopstyle
qml-module-qt-labs-folderlistmodel qml-module-qt-labs-settings qml-module-qtgraphicaleffects qml-module-qtqml qml-module-qtqml-models2 qml-module-qtquick-controls2 qml-module-qtquick-dialogs qml-module-qtquick-layouts qml-module-qtquick-localstorage
qml-module-qtquick-privatewidgets qml-module-qtquick-templates2 qml-module-qtquick-virtualkeyboard qml-module-qtquick-window2 qml-module-qtquick-xmllistmodel qml-module-qtquick2 qml6-module-org-kde-kirigami2 qml6-module-org-kde-kquickcontrolsaddons qml6-module-org-kde-pipewire
qml6-module-org-kde-qqc2desktopstyle qml6-module-qt-labs-folderlistmodel qml6-module-qt-labs-platform qml6-module-qt-labs-qmlmodels qml6-module-qt-labs-settings qml6-module-qt5compat-graphicaleffects qml6-module-qtqml qml6-module-qtqml-models qml6-module-qtquick
qml6-module-qtquick-controls qml6-module-qtquick-dialogs qml6-module-qtquick-layouts qml6-module-qtquick-particles qml6-module-qtquick-templates qml6-module-qtquick-window qt5-gtk-platformtheme qt5-image-formats-plugins qt5-phonon qt5-phonon-backend-vlc qt6-5compat qt6-base
qt6-charts qt6-declarative qt6-gtk-platformtheme qt6-multimedia qt6-phonon qt6-phonon-backend-vlc qt6-positioning qt6-qpa-plugins qt6-quick3d qt6-quicktimeline qt6-sensors qt6-serialport qt6-shadertools qt6-speech qt6-svg qt6-tools qt6-translations qt6-translations-l10n
qt6-virtualkeyboard qt6-wayland qt6-webchannel qt6-webengine qt6-webview qtspeech5-speechd-plugin qttranslations5-l10n qtvirtualkeyboard-plugin qtwayland5 rfkill sddm sddm-theme-breeze sddm-theme-maya util-linux uuid-runtime xdg-user-dirs xserver-common xserver-xorg-core
xserver-xorg-legacy
204 upgraded, 8 newly installed, 0 to remove and 1 not upgraded.

[Snowhog]

Working fine after a restart, except I have no sound. Sound isn't muted. Applicable Plasma Workspace Notifications marked and tested. No sound.

This issue was posted about in a separate thread, and resolved. Had my volume turned all the way down in the Host PC (my iMac).

[Beerislife]

No message, just a black screen and a mouse pointer. At least the pointer was the correct one!

[oshunluvr]

I had the same thing and just entered terminal mode, run apt update && apt full-upgrade and rebooted.

All good now.

[joneall]

I had the same thing and just entered terminal mode, run apt update && apt full-upgrade and rebooted.

All good now.

How do I enter terminal mode? If it's the alt-del-F2 trick, that does not work for me. I never get a login screen, just the black screen with the message. If I do it now, the message is not there, but the black screen is.

[oshunluvr]

CRTL-Alt-F3

log in

[joneall]

CRTL-Alt-F3

log in

After insisting several times on the ctl-alt-F3, i managed to login and that did the trick. Wonder what the problem was. An incomplete set of updates?

[oshunluvr]

After insisting several times on the ctl-alt-F3, i managed to login and that did the trick. Wonder what the problem was. An incomplete set of updates?

In my case it sure was, so I think that's the answer. My system updates itself at 5:30am. When I started using it around 8 a couple things weren't right - like Dolphin didn't respond, etc., so I rebooted and got the black screen and mouse cursor. I immediately did the second update and rebooted and all is well.

[Beerislife]

In my case installing any Japanese Input Method (ibus-anthy, fctix-mozc, fcitx5) hangs the Plasma 6 desktop after the login screen!

Just a black screen and a mouse pointer.