I upgraded Kubuntu to 14.04 today and it is a disaster!

The system booted to a usable desktop, but lost some settings related to the external monitor I'm using. I got that fixed and shut down for a complete backup of the root partition (/home is separate).

When I restarted the system, I got a screen with the default wallpaper but *nothing* else. No icons, no panel, nothing. Reboot - same thing.

Correction: there was an Activities button in the upper right corner.

I renamed ~/.kde to start over and have a usable desktop, but I cannot add anything to the panel. I get frequent crashes, but the crash reporter always says not enough information to submit a report. Virtal Desktops are unusable. Any attempt to configure them in the System Settings menu results in nothing happening. The window hangs and only comes back to life after I shift focus away and back.

How do I recover my desktop? Besides restoring from backup?

Thanks
Jim

I'd try and create a test user, log on as test user and see if everything is normal. If it is then the trouble is somewhere in your home directory, not necessarily in ~/.kde. My 2¢.

By hiding .kde and letting the system create a new directory, I'm effectively a new user and it works. The problem appeared to be that the upgraded KDE did not handle the previous version's configuration very well.

I restored .kde and ran
It took a long time to answer all the questions, and 2 tries to login, but now I have everything back to normal. I do not know what specifically fixed things. The first try, after enabling only the external monitor, resulted in a black screen with a tiny cursor. The cursor moved with the mouse, but there was no response from clicks or key-presses. The second try worked.