Black Screen After Loging into my wayland session

[BarelyAlive]

I've been using Kubuntu for some time now. But recently I've been experiencing black screens without my cursor whenever i logged into my wayland session. My X11 session still works nonetheless.

Specifications:

• KDE Plasma ver: 6.3.4
• KDE Frameworks ver: 6.12.0
• Qt ver: 6.8.3
• Kernel ver: 6.14.0-15-generic(64bit)
• Graphics platform: X11

[Schwarzer Kater]

Something is not right here (or very probably you don't use Kubuntu 24.04.x LTS)…

For Kubuntu 24.04 LTS it should be:

Operating System: Kubuntu 24.04
KDE Plasma Version: 5.27.12
KDE Frameworks Version: 5.115.0
Qt Version: 5.15.13
Kernel Version: 6.17.0-29-generic (64-bit)​

Btw: Kubuntu releases except 24.04 LTS, 25.10 (and this one only until July 2026) and 26.04 LTS are not officially supported anymore.

PS: and welcome, of course.

[die.boer]

• KDE Plasma ver: 6.3.4
• KDE Frameworks ver: 6.12.0
• Qt ver: 6.8.3
• Kernel ver: 6.14.0-15-generic(64bit)
• Graphics platform: X11

those are for Kubuntu 25.04

[die.boer]

please post outputs of these

lspci -k | grep -A 3 -E "VGA|3D|Display"

journalctl -b --grep=kwin

journalctl -b --grep=wayland

are you using AMD/NVIDIA/Intel ?
(the journalctl commands you can do in X11)

PS:try this 1st

mv ~/.config/kwinrc ~/.config/kwinrc.backup

mv ~/.local/share/kscreen ~/.local/share/kscreen.backup​

then reboot and try wayland again

[BarelyAlive]

Code 1:

00:02.0 VGA compatible controller: Intel Corporation HD Graphics 500 (rev 0b)
    Subsystem: Lenovo Device 39bf
    Kernel driver in use: i915
    Kernel modules: i915​

Code 2:

May 29 09:10:59 KillMe systemd[1486]: Starting plasma-kwin_x11.service - KDE Window Manager...
May 29 09:11:02 KillMe systemd[1486]: Started plasma-kwin_x11.service - KDE Window Manager.
May 29 09:11:50 KillMe kwin_x11[1782]: Module 'org.kde.kwin.decoration' does not contain a module identifier directive - it cannot be protected from external registrations.
May 29 13:54:44 KillMe kwin_x11[1782]: kwin_core: XCB error: 152 (BadDamage), sequence: 47286, resource id: 20989684, major code: 143 (DAMAGE), minor code: 3 (Subtract)
May 29 14:00:07 KillMe kwin_x11[1782]: qt.qml.context: file:///usr/lib/x86_64-linux-gnu/qt6/qml/org/kde/kwin/decoration/DecorationButton.qml:46:9 Parameter "mouse" is not declared. Injection of parameters into signal handlers is deprecated. Use JavaScript functions with formal parameters instead.
May 29 14:00:52 KillMe kwin_x11[1782]: kwin_core: XCB error: 152 (BadDamage), sequence: 56128, resource id: 20999035, major code: 143 (DAMAGE), minor code: 3 (Subtract)

Code 3:

May 29 09:09:40 KillMe sddm-greeter-qt6[1419]: Reading from "/usr/local/share/wayland-sessions/kubuntu-live-environment.desktop"
May 29 09:09:40 KillMe sddm-greeter-qt6[1419]: Reading from "/usr/share/wayland-sessions/kubuntu-live-environment.desktop"
May 29 09:09:40 KillMe sddm-greeter-qt6[1419]: Reading from "/usr/local/share/wayland-sessions/plasma.desktop"
May 29 09:09:40 KillMe sddm-greeter-qt6[1419]: Reading from "/usr/share/wayland-sessions/plasma.desktop"
May 29 09:11:09 KillMe systemd[1486]: Starting app-org.kde.xwaylandvideobridge@autostart.service - Xwayland Video Bridge...
May 29 09:11:09 KillMe systemd[1486]: Started app-org.kde.xwaylandvideobridge@autostart.service - Xwayland Video Bridge.​

Note:
It still gave me a black screen even after i tried the last code you gave. (I use Intel)

[die.boer]

please check if wayland works for a brand new user, create one with

sudo adduser testwayland

then we can see if it is configuration-related or system graphics stack related

[BarelyAlive]

The Wayland session worked on the new user.

[die.boer]

ok that's good
run these ,one at a time (from X11 session)

mkdir -p ~/plasma-backup

mv ~/.config/plasma-org.kde.plasma.desktop-appletsrc ~/plasma-backup/

mv ~/.config/plasmashellrc ~/plasma-backup/

mv ~/.config/kdeglobals ~/plasma-backup/

mv ~/.cache/plasmashell* ~/plasma-backup/ 2>/dev/null

mv ~/.cache/ksycoca* ~/plasma-backup/ 2>/dev/null

mv ~/.local/share/plasma ~/plasma-backup/ 2>/dev/null​

rm -rf ~/.cache/*qml*

rm -rf ~/.cache/plasma*​

reboot (just type reboot in terminal and hit enter ,btw ) , and test wayland again (with your normal user of course)