But when I start it the program hangs. It will not start. I am stuck with two windows - one is the cryptomator window which will not respond to anything (I have to use xkill to get rid of it) and the other is ‘update check’ which presents a small (10mmx6mm vertical) window.
The small “update check” window is a modal dialog. That means, you have to choose an option. That’s why it’s probably blocking the main window. Or are you also unable to interact with the “update check” window?
Additionally you can remove the repository (location from which you can cryptomator again): sudo add-apt-repository --remove ppa:sebastian-stenzel/cryptomator