src/Pure/System/isabelle_process.ML

--- a/src/Pure/System/isabelle_process.ML	Sat Mar 18 13:06:10 2017 +0100
+++ b/src/Pure/System/isabelle_process.ML	Sat Mar 18 13:15:07 2017 +0100
@@ -206,6 +206,8 @@
     val _ = loop channel;
     val _ = Message_Channel.shutdown msg_channel;
     val _ = Private_Output.init_channels ();
+
+    val _ = print_mode := [];
   in () end);