Try switch to text console (Ctrl+Alt+F1), log in and remove file $HOME/.config/xfce4/xfconf/xfce-perchannel-xml/displays.xml, log out from text console, switch back to graphical login screen and try...
Type: Posts; User: ivoshm; Keyword(s):
Try switch to text console (Ctrl+Alt+F1), log in and remove file $HOME/.config/xfce4/xfconf/xfce-perchannel-xml/displays.xml, log out from text console, switch back to graphical login screen and try...