diff --git a/session.c b/session.c
index d9d9c486..75028882 100644
--- a/session.c
+++ b/session.c
@@ -501,7 +501,8 @@ session_set_current(struct session *s, struct winlink *wl)
 	winlink_stack_push(&s->lastw, s->curw);
 	s->curw = wl;
 	if (options_get_number(global_options, "focus-events")) {
-		window_update_focus(old->window);
+		if (old != NULL)
+			window_update_focus(old->window);
 		window_update_focus(wl->window);
 	}
 	winlink_clear_flags(wl);