Hello,

I've just upgraded to plasma 5.26.
After reboot and login in I have no desktop or krunner or launcher.

Starting konsole with ctrl-alt-t does work. So for test, running plasmashell in terminal doesn't do a thing. There's already a plasmashell process running.

Actually, it takes a long time, 10+ minutes, for the launcher, desktop and krunner to be functional and displayed.
Coincidently it's the same time that I have set plasma desktop wallpaper changer to slideshow to change every 10 minutes.
If I try to change that setting, I loose again all desktop, krunner and launcher.

so I've tried this:
-revert to nouveau video driver instead of nvidia driver.
-reboot. No effect, same problem.
-try to change the wallpaper slide show to 5 minutes instead of 10. Click ok. Effect = Immediatly I loose desktop, krunner and launcher.
-revert to nvidia driver and reboot.
-login. Problem still there. But after 5 minutes, instead of the 10, the desktop, launcher and krunner are back.

help.

Thanks.

When I tried to update to 5.26 with Discover it proposed the list of changing packages, in which two packages were proposed to be removed: libkwineffects13 and libkwinglutils13, and no newer versions of libkwineffects* and libkwinglutils* were proposed to be installed instead. This fact alarmed me, ind I decided to delay the update until this problem will be solved. It seems, that this could be possible reason of the trouble described by you.

"apt search libkwinglutils" and "apt search libkwineffects" reveal that those 2 libs were replaced by version 14, so the problem might not be that.

I am sorry for misinforming, actually libkwineffects14 and libkwinglutils14 are present, and all updates applied successfully on 20.04 system, everything works fine (almost )with 5.26.

Same issue here on Plasma 5.24.6 in Kubuntu.

It happens only sometimes and sometimes everything is great for 2 weeks. Restarting might help if not restarting once, then restarting twice.

Sometimes panels might appear after some time, but usually not at all. When it breaks Alt + F2 does not bring krunner pannel.
Running plasmashell --replace in terminal also does not help.

I created a bug report at https://bugs.kde.org/show_bug.cgi?id=460324