--- gnome-session-3.6.2/gnome-session/gsm-systemd.c.orig	2012-12-23 15:29:22.606831106 +0400
+++ gnome-session-3.6.2/gnome-session/gsm-systemd.c	2012-12-23 15:32:16.708010379 +0400
@@ -350,6 +350,7 @@ gsm_systemd_can_stop (GsmSystem *system)
         gchar *rv;
         GVariant *res;
         gboolean can_stop;
+        GError *error = NULL;
 
         res = g_dbus_proxy_call_sync (manager->priv->sd_proxy,
                                       "CanPowerOff",
@@ -357,7 +358,13 @@ gsm_systemd_can_stop (GsmSystem *system)
                                       0,
                                       G_MAXINT,
                                       NULL,
-                                      NULL);
+                                      &error);
+        if (!res) {
+                g_warning ("Unable to call 'CanPowerOff': %s", error->message);
+                g_error_free (error);
+                return FALSE;
+        }
+
         g_variant_get (res, "(s)", &rv);
         g_variant_unref (res);