As from the title I launched the upgrade from Diskover and returning to my PC I discovered it fixed in a black screen with only the mouse cursor avaiable.


Rebooting resulted in going trough a black screen with only something like [ 6.370678] in the upper left corner and next returning to previous screen.


Coming trough the boot manager I tried to go to root CLI, and using apt and dpkg updated everyting avaiable, in the end coming trough this screen


https://imgur.com/a/YY0S86B


without being able to login.



Wanted to ask if there is any option to solve this or will be better to (again) resintall everything.

Hi davide445,

From what I could read of the error message on your login screen in the picture you provided, you seem to have an issue with your display manager, which, again, from what I can read, is SDDM. SDDM seems to be complaining that it cannot find the "theme" it is expecting (missing components).

I am curious : can you login normally in another TTY ? I don't use KDE, but display managers / GUIs often default to TTY7 so if you toggle over to TTY1 or TTY2, you could try logging into a command line session there and see if that is functional. If it is, perhaps you could try reinstalling SDDM with your package manager from the command line and then rebooting and trying your usual SDDM login.

Let us know how that works out.

Cheers,

Rick

1 members found this post helpful.

Apologize for my ignorance, but for TTY you mean software emulated teletype?

I don't know how is possible to access one from that login screen, was reading an article that in theory will be possible using Ctrl+Alt+F1/2/3 etc to access it, if this is the case I can try.

In any case I can have root CLI access from the "other" Linux boot options, so can try to reset SDDM using something like

sudo dpkg-reconfigure sddm

Just Googling for the solution, didn't have the know-how about this topic.

If this will not work I think after almost four years enjoying latest KDE Plasma but fighting against Neon upgrade instabilities I will revert from KDE Neon to Kubuntu.

Hi davide445,

Sorry - by TTY I am just referring to a CLI session. When you boot a linux distro, it presents you with a login screen, either graphical (as with a display manager such as SDDM) or a simple command line. Several CLI sessions are usually created at each boot - to toggle between them you use the CTRL-ALT-F1 (or 2 or 3 ... etc. , up to 7) key sequence. Since linux is a multi-user / multi-session environment, you can have several simultaneous login sessions active.

So you could switch over to one of those CLI sessions, login, and attempt to correct your issue with SDDM. If the dpkg-reconfigure command you mention doesn't work, perhaps a removal-reinstallation of the package and its dependencies would help.

Let us know how you make out !

Rick

1 members found this post helpful.

Don't feel alone. SDDM never worked right for me in Neon 20.04. Since upgrading to 22.04, SDDM behaves like it should work, but it always rejects the password, which works on the vttys, which allows me to run Plasma via startx.

Incredibly I sorted out..

Switching to another TTY give me a console on my user, updating or reinstalling SDDM didn't produce any meaningful result but in the process I noticed there was again an alert an upgrade 20.04-->22.04 was available.

I launched the upgrade by CLI and this time seems cleaned some problem was generated during my remote unattended upgrade, due I have back my Plasma session and all seems working well.

Looking at some errors might have played a role the fact I was using Wayland compositor and having activated NoMachine since I'm using it to work remotelly.
Seems they didn't play well together, so that even with the restored Plasma was impossible to connect remotelly, returning to X11 all is working fine.

Give kudos to all the people working on this packaging and upgrade system for enabling an user at absymal level like me to get things working, anyway I need to point out that working in tech since many years I always have had the info Windows was a mess and Linux is the true stable experience.

In four years I have this PC I have installed hundred of different packages/frameworks/applications/updates on the Windows installation that's still the same working since I assembled it. On Linux, at least KDE Neon, it's always some adrenaline coming and more than once a year I will need to deal with reinstallation/troubleshooting of this kind.

I suppose server side is different, and possibly next time I will need to switch also to Kubuntu to get a more stable experience, with a bit of regret since I like seeing Plasma evolving.