--- loncom/interface/lonprintout.pm	2017/01/30 19:45:05	1.657
+++ loncom/interface/lonprintout.pm	2017/05/29 22:43:07	1.658
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Printout
 #
-# $Id: lonprintout.pm,v 1.657 2017/01/30 19:45:05 raeburn Exp $
+# $Id: lonprintout.pm,v 1.658 2017/05/29 22:43:07 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -3452,7 +3452,9 @@ ENDPART
         if ($env{'request.enc'}) {
             $url = &Apache::lonenc::encrypted($url); 
         }
-        $URLback = $url.($url =~ /\?/) ? '&':'?'.'symb='.$helper->{VARS}{'symb'};
+        if ($url ne '') {
+            $URLback = $url.(($url =~ /\?/) ? '&':'?').'symb='.$helper->{VARS}{'symb'};
+        }
     }
     #
     # Final adjustment of the font size: