Anybody has seen this in F24:
Booting into runlevel 5, login in a gnome session, open a gnome terminal and enter: "sudo init 3".
Then goto a tty by CtrlAltFn, login as root and say: init 5. Then the box does not completely boot back to runlevel 5 but remains in some runlevel interstage where it's impossible to login again into a gnome session.