diff -r 87be91e6d486 -r c8d141cce517 src/HOL/Tools/Sledgehammer/sledgehammer_isar.ML
--- a/src/HOL/Tools/Sledgehammer/sledgehammer_isar.ML	Mon Nov 12 12:28:19 2012 +0100
+++ b/src/HOL/Tools/Sledgehammer/sledgehammer_isar.ML	Mon Nov 12 14:11:51 2012 +0100
@@ -373,6 +373,7 @@
   let
     val ctxt = Proof.context_of state
     val override_params = override_params |> map (normalize_raw_param ctxt)
+    val _ = Isabelle_System.mkdir (Path.explode (getenv "ISABELLE_TMP"))
   in
     if subcommand = runN then
       let val i = the_default 1 opt_i in