diff -r 76fa673eee8b -r 15bb09ca0378 src/Pure/ProofGeneral/proof_general_emacs.ML
--- a/src/Pure/ProofGeneral/proof_general_emacs.ML	Tue Sep 29 11:48:32 2009 +0200
+++ b/src/Pure/ProofGeneral/proof_general_emacs.ML	Tue Sep 29 11:49:22 2009 +0200
@@ -226,7 +226,7 @@
 
 (* init *)
 
-val initialized = ref false;
+val initialized = Unsynchronized.ref false;
 
 fun init false = panic "No Proof General interface support for Isabelle/classic mode."
   | init true =
@@ -239,9 +239,9 @@
           ProofGeneralPgip.init_pgip_channel (! Output.priority_fn);
           setup_thy_loader ();
           setup_present_hook ();
-          set initialized);
+          Unsynchronized.set initialized);
         sync_thy_loader ();
-       change print_mode (update (op =) proof_generalN);
+       Unsynchronized.change print_mode (update (op =) proof_generalN);
        Isar.toplevel_loop {init = true, welcome = true, sync = true, secure = Secure.is_secure ()});
 
 end;