Well, I tried the commands listed by bcoosley above, and now I only get a black screen when I logon. (Although the shortcut commands still work.) So... if anyone has an idea of what may have happened and how to fix it, please let me know.

Could be related to compositing enabled but not working.

Edit your $(kde4-config --localprefix)/share/config/kwinrc file and set Enabled=false in the compositing section.

(of course, do this without a started KDE environment.)

neverendingo wrote:Could be related to compositing enabled but not working.

Edit your $(kde4-config --localprefix)/share/config/kwinrc file and set Enabled=false in the compositing section.

(of course, do this without a started KDE environment.)

Thanks for responding... but changing the config file didn't help. Further to this situation, it appears that this failure has affected all my KDE4 users (earlier I had tried KDE4 with a different user and the plasmoid desktop worked perfectly), now it will not start either. I even tried creating a new user -- didn't help. Then I tried removing the desktop and reinstalling, and that didn't help either. (However I think that removing the desktop doesn't delete the config files and settings -- if that's related to the problem.)

I'm now working in Gnome again. Grrrr!!!!
Any other ideas?

Can you verify that all KDE packages are fully up to date, and that kdebase-runtime and kdelibs5 are installed?

bcooksley wrote:Can you verify that all KDE packages are fully up to date, and that kdebase-runtime and kdelibs5 are installed?

Synaptic shows that they are installed.

I've searched the web for other similar instances to mine. The closest I found was: http://kubuntuforums.net/forums/index.p ... =3105595.0 but this person never solved the problem either.

If you open Konsole using Alt + F2. Try running the following:

Code: Select all

plasma-desktop &

bcooksley wrote:If you open Konsole using Alt + F2. Try running the following:

Code: Select all

plasma-desktop &

I saw some error message, which I can't copy because it was followed by an infinite loop of:
QGraphicsGridLayout::itemAt: invalid index 1
QGraphicsGridLayout::itemAt: invalid index 2
QGraphicsGridLayout::itemAt: invalid index 2
QGraphicsGridLayout::itemAt: invalid index 2
QGraphicsGridLayout::itemAt: invalid index 1
QGraphicsGridLayout::itemAt: invalid index 2
QGraphicsGridLayout::itemAt: invalid index 2
QGraphicsGridLayout::itemAt: invalid index 2

See the bug report for similar problem: https://bugs.kde.org/show_bug.cgi?id=202520

Here's something else that's interesting. I tried renaming the .kde and .kde4 directories, and kde started (c/w plasmoid-desktop)! Only problem is that when I exited the session and then logged on again, I got the black screen again. (This is can be replicated.) Does this help?

Thanks everyone who responded to my messages. I did get KDE4 working again. I uninstalled (not completely though) all version 4.3.1 apps and files, deleted the kde and kde4 folders, reinstalled version KDE v4.2, then upgraded to version 4.3.1. Everything seems okay now with all users (whereas originally my main user could not load 4.3.1).