diff -r ecb746bca732 -r 5b21661fe618 src/Tools/quickcheck.ML
--- a/src/Tools/quickcheck.ML	Sat Oct 17 15:55:57 2009 +0200
+++ b/src/Tools/quickcheck.ML	Sat Oct 17 15:57:51 2009 +0200
@@ -24,7 +24,7 @@
 
 val _ =
   ProofGeneralPgip.add_preference Preferences.category_tracing
-  (setmp auto true (fn () =>
+  (setmp_CRITICAL auto true (fn () =>
     Preferences.bool_pref auto
       "auto-quickcheck"
       "Whether to enable quickcheck automatically.") ());