I recently upgraded kde4 to the factory repo for 11
I had tried several times before, but plasma crashed at every attempt to login.
This time I renamed .kde4 to .kde4old - to create a new.kde4 at login
It worked!
But logout and try to log back in
I get a blank grey screen. No error seen.
If I delete the newly formed .kde4 folder and try again - It is fine. But logout and back in - the same grey screen.