diff --git a/js/ui/screenShield.js b/js/ui/screenShield.js
index 1c1dca6cf..32ef1ca9e 100644
--- a/js/ui/screenShield.js
+++ b/js/ui/screenShield.js
@@ -920,8 +920,10 @@ const ScreenShield = new Lang.Class({
         this._lockScreenState = MessageTray.State.HIDDEN;
         this._lockScreenGroup.hide();
 
-        this._dialog.actor.grab_key_focus();
-        this._dialog.actor.navigate_focus(null, Gtk.DirectionType.TAB_FORWARD, false);
+        if (this._dialog) {
+            this._dialog.actor.grab_key_focus();
+            this._dialog.actor.navigate_focus(null, Gtk.DirectionType.TAB_FORWARD, false);
+        }
     },
 
     _hideLockScreen: function(animate, velocity) {