This is the first time I've asked a question here.

I am running Kubuntu 18.4. I decided to explore the "alternative" main menus accessible by right clicking on the main KDE launcher.

I selected the "full screen" alternative. The screen went to unresponsive black. There is nothing to click on.

I can alt-tab and bring up open programs. But they sit on top of the non-functional full-screen black menu alternative.

The black overlay prevents me accessing the menu to change this setting.

I can't find anything on Google or in these forums that addresses this issue.

Can anyone suggest a fix?

Thanks.

"Full screen" would be the Application Dashboard. Are you sure your Kubuntu 18.04 is fully updated? It is after all over 2 years old now, and the new LTS version, 20.04 is out, and there have been several updates of the 18.04 LTS version as well.
FWIW: can't reproduce this with current 20.04, so this might well be solved since quite some time already.

Does a right click on the screen bring anything up?
You could also just switch to a terminal with Ctrl+Alt+F1 and kill plasmashell, this should bring you back to the SDDM login screen

Thank you for your reply Mamarok. Yes, it is the application dashboard that's failing. It seems that the overlay dark background is loading but nothing else. So there's nothing to click on.

There's no right click at all. Ctrl-Alt-F1 does not bring up a terminal.

However, Alt-F2 will bring up Quick Search and I can get to a terminal or any other program from there. I have tried switching desktop themes with System Settings (a Google search suggestion) but no change.

How do I kill plasmashell? No method found with Google is working.

FYI -- I was able to create a new administrative user through a Cinnamon desktop (which I had installed for evaluation when I first installed 18.04 but decided I still preferred the KDE desktop).

That new administrator user can login to kubuntu, access all installed programs, but can't mount any of the other partitions on the drive where I keep my actual working files.

Neither "Kinfocenter" nor "About System" give any information for Kubuntu itself other than it is 18.04. Other info:

KDE Plsma version 5.12.9
KDE Frameworks Version 5.44.0
QT Version 5.9.5
Kernal version 5.3.0-51-generic
64 bit OS
Intel i7 CPU
16 GB RAM

Thanks for your help. I've been using Kubuntu since 12.04.

the command

Code: Select all

 killall plasmashell

should just work.

FWIW: it might be a good idea to update your installation: https://help.ubuntu.com/community/FocalUpgrades/Kubuntu

Thanks again Mamarok.

Any variation of kill plasmashell returned error message "No such process". So it seems plasmashell was not loading for my original user, but would load for the new user I created.

I decided to try to upgrade from 18.04 to 20.04. Long story short, the upgrade failed and the system became non-bootable for all users. Trying to repair packages in recovery mode failed as well. Frustrating.

So I installed 20.04 to another partition and I'm working through getting it set up for my workflow. I am able to use the application dashboard and quite like it. I've seen similar dashboards in Fedora and Deepin but always found their layout and icon size unattractive so never used.

Again, thanks for your help.