App stuck on this loading screen, possibly 'cause a second instance was already open.

[Furimanejo]

[ni1chigo2115]

same (white blank)

[A B]

Same here. Console gives this error:
(intiface_central:3751): Gdk-CRITICAL **: 15:41:21.837: gdk_window_get_state: assertion 'GDK_IS_WINDOW (window)' failed