Hit the 'unable to log in' issue after update to Plasma 6

My desktop was a bit behind on patches, and I just hit all of the issues with the broken update to Plasma 6 today.

I’ve been following a bunch of the threads about this but the forum won’t let me link to them here.

What I’ve done so far:

  • This has succeeded: sudo pkcon install libdecor-0-0 libsdl2-2.0-0 plasma-desktop plasma-desktop-data --allow-reinstall
  • Several rounds of sudo apt autoremove and sudo apt dist-upgrade, neither of these commands are doing more work at present
  • This step as well: sudo pkcon install kf6-kfilemetadata kio-extras kio-extras5 kio-extras5-data krename libk3b8 libk3b8-extracodecs libtag1v5 libtag1v5-vanilla python3-update-manager --allow-reinstall

And, output of startplasma-wayland 2>&1 | tee output.log

Error: could not determine $DISPLAY.
Error: Can not contact kdeinit5!
org.kde.startup: "kdeinit5_shutdown" QList() exited with code 255

So this suggests that something Plasma 5 related is still hanging around my system, but I don’t know what to do about it.


Well. I found a workaround: the wayland/x11 picker on the login screen is working fine, and so is the x11 session. Still no idea what’s going wrong with wayland exactly. I’m going to assume this install just has a limited shelf life from here out, given the failed update.