I am currently upgrading from 15.10 to 16.04 and the upgrader hangs in a situation you can see in the screenshot
The text in the lower window means "gconf2" could not be installed. The Upgrade will be continued, but the package "gconf2" could be in a broken state. Please consider reporting this bug, which I did. When I click on the button Schließen (Close), the window just reappears.
If there is nothing I can do, would it be best to just do a fresh install of 16.04?
Edit: I cannot start the startup disk creator, most likely due to the ongoing upgrade. So what options do I have?