src/Pure/PIDE/batch_session.scala

--- a/src/Pure/PIDE/batch_session.scala	Sat Feb 13 20:01:48 2016 +0100
+++ b/src/Pure/PIDE/batch_session.scala	Sat Feb 13 20:41:56 2016 +0100
@@ -58,7 +58,7 @@
         case _ =>
       }
 
-    prover_session.start("Isabelle", List("-r", "-q", parent_session))
+    prover_session.start("Isabelle", "-r -q " + quote(parent_session))
 
     batch_session
   }