Some time ago my KDE Neon installation became unbootable. II thought I should be able to sort it all out by myself, so I haven't made notes of everything I've done.

I managed to improve things slightly using one or more of my recovery mode options, but even now I have to force a text login prompt by pressing Ctrl+Alt+F4, then I can type a user name and password, which enables me to log in. After that, I thought I could start KDE Plasma just by typing startx or even initx, but neither of these commands will work.

I think there should be a simple Terminal command I can type to fix this, but nothing seems to work. I assume I have no Internet connection unless I use a wired connection, but I'm not sure that's working either. I thought I could fix it with the command "sudio apt install task-kde-desktop" or a variation of this, but nothing worked. I also read a more generic tip about kubuntu, but I don't think I'm supposed to use that in KDE Neon.

How can I restore my KDE Plasma desktop?

What specific errors do you get when running the startx command?
These are very important as we can't tell much of what is happening, without these, as well as what specific things you had tried previously, and maybe why you tried them.

But the exact error messages you get with startx are a good place to begin.

There's no error message from startx but all that happens is that a mouse pointer appears on a black screen, I can move the pointer around, but nothing else happens.

paulbr wrote:There's no error message from startx but all that happens is that a mouse pointer appears on a black screen, I can move the pointer around, but nothing else happens.

Ok that is a start.
Now, if hitting alt-f2 brings up krunner try typing this in it:

Code: Select all

plasmashell

Often the black screen with cursor is a sign that plasmashell (the desktop bits) has crashed and often restarting it gets things up and running. At least you may be able to investigate things, update your system etc.

The result of typing plasmashell is "relocation error" followed by a whole load of stuff I don't understand. I can't even work out how to upload a pic of my screenshot on here. I took some pics of the whole screen, as well as some closeups, but I can only read the text from the closeups, meaning some text is off the screen. From what I can see it's "relocation error: /usr/lib/x86_64-linux-gnu/lib", then some more text off the screen, ending with "_5_PRIVATE_API not defined in file libQt5Core.so.5 with" and some more text off the screen.

Of course, my problems start when the SDDM won't give me its login screen, so it seems that's what needs to be fixed instead.

No, it is much more than that, if it were just SDDM, then startx would get you to your normal desktop. Using krunner, try opening Discover, or konsoie, and try updating your system if they open. Or use ctrl-alt-f2 to get to a tty, log in, and try updating there:

Code: Select all

sudo apt update
sudo apt full-upgrade

I am suggesting apt here, as it will give better error messages.

Note that since krunner is opening, you should be able to run many if not most normal applications from there, like your web browser, system settings, etc.


Without knowing the specific of what you have done to try and fix things, it is hard to say where to go, so trying to update the system is a good place to start.

I don't remember ever hearing of krunner before you mentioned it earlier in this thread. Pressing Alt+F2 only took me back to the login prompt! Unless I can launch it by typing krunner, I'll just have to follow your advice about using the terminal commands to do an update. Of course, I need to be online to carry out the update. Using a wired connection I could start networking from recovery mode, but if that doesn't stay connected then I'd need to type lots of ipconfig commands which I don't understand.

I think I got into this mess because the laptop I'm using is one I originally bought and set up for a friend who's technophobic and on medication. I downloaded lots of videos onto it because I knew he couldn't work out how to stream videos, but hoped he might learn. I showed him how to do this in a pub. I then saw that his hands were shaking so badly from his medication that he couldn't really use the mouse pad or even a mouse! After he took the laptop home he ignored my instructions completely by opening a text file which automatically opened Kwrite, which I didn't even know was installed on the system. That didn't do any harm, but then instead of using Kodi or VLC he tried to load and play a video file into Kwrite! Instead of giving an error message, Kwrite displayed lots of gibberish on the screen. My friend was so shocked by this that he didn't take things any further. After this he built up a medication induced fantasy that the laptop was a death trap which would catch fire, then he threw it away! I persuaded him to send it back to me. After this, ther were still lots of video files on the KDE Neon partition, as well as some on the Elementary OS partition. Some time ago, I had similar problems to the ones I'm having now, due to lack of space on my hard drive, thanks to video files. I can't remember which distro I was using, but it was probably Mint, Ubuntu, or Manjaro. I advise people to make sure their partitions don't get nearly full up with video files, otherwise they'll become unbootable. Unfortunately, Linux doesn't give many warnings when this is about to happen. I don't know how to make it warn me when the storage space drops below 2Gb for example.

just alt-f2. ctrl-alt-f2(3, 4, etc) is the one that switches to the tty.
Or use alt-space, as a secondary shortcut.

If Plasma itself is not running, that does not mean that you don't have networking, especially if it is set to connect automatically to wifi. Those applications and things in the background are likely still running as they normally would. If you can open a browser, you can tell right away.

Thanks! I used "sudo apt update" and that worked! I didn't try the full ugrade in case my video files got deleted. I don't know if I posted in the right place, but I'm using KDE Neon. I was then prompted that in KDE Neon I had to type something like "pkcon update" after that, but the update was carried out, then I logged out and pressed Ctrl+Alt+Del to restart my laptop and finally I got the graphic login screen, whether it's SDDM or whatever it is. I found that it had been so long since I was able to use this that it didn't know the password for my current WiFi connection which I've had since August 26! I must have been using Elementary OS ever since then.

paulbr wrote:Thanks! I used "sudo apt update" and that worked! I didn't try the full ugrade in case my video files got deleted. I don't know if I posted in the right place, but I'm using KDE Neon. I was then prompted that in KDE Neon I had to type something like "pkcon update" after that, but the update was carried out, then I logged out and pressed Ctrl+Alt+Del to restart my laptop and finally I got the graphic login screen, whether it's SDDM or whatever it is. I found that it had been so long since I was able to use this that it didn't know the password for my current WiFi connection which I've had since August 26! I must have been using Elementary OS ever since then.

Glad you got it sorted!!

Doing a full-upgrade will not remove any videos or other files, it is the correct method to stay up to date, if using apt in the terminal. It performs the same function as pkcon update. Normally, use Discover to stay up to date, or use pkcon in the terminal.

After doing the above, I now get offered an upgrade in a box whenever I log in, at the same time as my WiFi connection is activated. Clicking on Upgrade doesn't carry this out, though. There's also a message telling me to perform all updates before doing the upgrade. I can't find out what updates these are though. Should I type the Terminal command you listed above to do a full upgrade, or would that break my KDE Neon installation again? Perhaps I could type the update command listed above before the full upgrade command.

So I will assume that you are still on the now-old 18.04 based Neon, and the system is prompting you to upgrade to the current 20.04 base.

The commands I gave will just keep your current install up to date, it will not upgrade you to the new 20.04. Same as if you use Discover to check and install updates. Running pkcon update or Discover is all that is needed.

As to attempting the upgrade, I am not sure about attempting that. While I personally would jump right in, there is always a chance the process will go bad. I'd stay put for the moment if things are working. You will get base Ubuntu OS updates for some time still (2023) but if they have not stopped already, you won't get any KDE and Plasma updates before very long. Not sure on when Neon stops providing updates to the old 18.04 base.

Seeing as the new release upgrader didn't work, it may be much safer to stay put instead of manually attempting the upgrade

Note that the official instructions say to log out and back in before starting the upgrade
https://community.kde.org/Neon/FocalUpgrades
There is a command to do the upgrade as well, but if the GUI is not working, I'd shy away from trying this.

I'm afraid I wasn't able to do a full upgrade because I didn't have enough space on my partition. Most of the space is taken up by video files. Now, the problem is back, but it may be worse than before. It happened when my laptop became unresponsive while trying to stream a video. What I get now is no graphic login, then after pressing Ctrl+Alt+F4 I can do a text login, but after that I immediately get a message that KDE Neon can't connected to something which it must connect to. There's no Internet connection, even with a LAN cable plugged in. I think I'll have to delete some video files before this can be sorted out. Should I delete them from my Elementary OS partitiion or from the text prompt in KDE Neon? Exactly what command do I need to delete them altogether? I've just checked using Dolphin from my Elementary OS partition and found that my KDE Neon partition now has 0 bytes free, so that must be them problem! Unfortunately, I don't remember getting any warning this was about to happen. After that, how can I get my KDE Plasma working again?

OK, that's it! I managed to delete some of the videos files from KDE Neon using Dolphin from my Elementary OS partition. After deleting just a few files, creating less than 1Gb of space, my graphic login screen was restored and KDE Neon is now working. So, the moral of this story is keep checking how much disk space remains on your partition, otherwise your installation will become unbootable!

claydoh wrote:No, it is much more than that, if it were just SDDM, then startx would get you to your normal desktop. Using krunner, try opening Discover, or konsoie, and try updating your system if they open. Or use ctrl-alt-f2 to get to a tty, log in, and try updating there:!

Code: Select all

sudo apt update
sudo apt full-upgrade

...

Thanks for this! I am using Kali, and the full-upgrade fixed my plasma.

The other problem, I had it on a chromebook and it was due to a full disk, just as the previous post, I solved it by deleting some files.

Thanks again!