Did you change any of the "preferred applications" via the menu (or via the cli-command "gnome-default-applications-properties").
If so this might be a duplicate of: https://bugs.launchpad.net/ubuntu/+bug/800927
Did you change any of the "preferred applications" via the menu (or via the cli-command "gnome- default- applications- properties" ).
If so this might be a duplicate of: https:/ /bugs.launchpad .net/ubuntu/ +bug/800927