--- xscreensaver-4.18/driver/lock.c.check-for-null-passwd-entry	2007-04-18 16:25:33.000000000 -0400
+++ xscreensaver-4.18/driver/lock.c.check-for-null-passwd-entry	2007-04-18 16:26:01.000000000 -0400
@@ -1289,7 +1289,7 @@ 
       */
       struct passwd *pw = getpwuid (getuid ());
       char *d = DisplayString (si->dpy);
-      char *u = (pw->pw_name ? pw->pw_name : "???");
+      char *u = (pw && pw->pw_name ? pw->pw_name : "???");
       int opt = 0;
       int fac = 0;