diff -r 5ec497351636 -r 3b4877fbd9cb src/Pure/Admin/isabelle_devel.scala
--- a/src/Pure/Admin/isabelle_devel.scala	Sun May 14 21:34:36 2017 +0200
+++ b/src/Pure/Admin/isabelle_devel.scala	Sun May 14 21:54:35 2017 +0200
@@ -25,7 +25,7 @@
   {
     val header = "Isabelle Development Resources"
 
-    Isabelle_System.mkdirs(root)
+    HTML.init_dir(root)
     File.write(root + Path.explode("index.html"),
       HTML.output_document(
         List(HTML.title(header)),