I upgraded my Kubuntu 15.10 machine to 16.04 yesterday. Everything was working fine. Today, I did a reboot. Upon logging in, my desktop doesn't show so I have a blank black screen. Thankfully, Plank was able to start so I have access to a terminal, file browser, and Chrome.
What can I do to fix this? I'm assuming this is a problem with Plasma, but I honestly don't know.