Linux Mint GUI stays black after login

Suddenly this happens: When I boot my noteback linux mint boots to the login screen. Then after I logged in the mouse cursor is visible centered on a black background. And thats where nothing more happens. I tried to use startx but same problem there...stays black.

One thing. I removed wpasupplicant package before this happened. I'm sure I saw some "cinnamon" removing while the removal processed. Might it be that my cinnamon - which is the GUI isn't it? - has been removed aswell?

I'd like to give you more debug log / informations - but I'm not familiar in doing so. I'm used to work in Terminal for coding but something need to get into GUI for browsing.

EDIT: When trying to switch cinnamon on the login screen (the lambda symbol) this error message appears

Might it be that there really is an issue with cinnamon after the removal of wpasupplicant package?

EDIT2: I found a link describing that error message above: forums.linuxmint.com/viewtopic.php They tell to sudo apt-get install --reinstall cinnamon. Funny thing is that I cannot connect to WIFI without GUI. Terminal needs wpasupplicant package which I recently removed ;) yeah!