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After updating from Kubuntu 24.10 (oracular) to Kubuntu 25.04 (plucky) the login screen is broken:

  • The background is white instead of the usual wallpaper
  • The bottom half of the screen is occupied by a gigantic visual keyboard (which can be hidden away)
  • In the middle of the screen the default user picture is shown with a text field for the password below it
  • Entering the password and pressing enter does not open the user session
  • The drop down menu for selecting the session is visible in the top left corner
  • The drop down menu for selecting the session has zero entries

As a result it is impossible to log in to the Plasma desktop environment using SDDM.

FedKad
  • 13,420
Stéphane Tréboux
  • 3,239

1 Answers1

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The update from Kubuntu 24.10 (oracular) to Kubuntu 25.04 (plucky) uninstalled the entire Plasma desktop environment. To install it again:

  1. From the broken login screen, press Ctrl+Alt+F3
  2. Wait a second, a black and white command line should appear
  3. Enter your user name
  4. Enter your user password
  5. Enter sudo apt-get install kubuntu-desktop
  6. Enter your user password (to run apt-get with elevated rights)
  7. Wait until the installation is done (when the output stops for a moment)
  8. Press Ctrl+Alt+Del to initiate a restart
  9. Wait for the computer to reboot

The login screen (SDDM) should be back to normal and you should be able to login.

Remarks:

  • You will need an Internet connection to download the missing packages. Using a LAN cable may be the easiest option.
  • After being able to log in, you may notice that some other packages are missing. In my case, Digikam and Firefox were removed too. You can install them again from your favorite package manager.
Stéphane Tréboux
  • 3,239