diff -r 735bea8d89c9 -r 674893679352 src/Pure/Thy/thy_load.scala
--- a/src/Pure/Thy/thy_load.scala	Thu Nov 29 23:12:50 2012 +0100
+++ b/src/Pure/Thy/thy_load.scala	Fri Nov 30 10:42:54 2012 +0100
@@ -47,7 +47,10 @@
   {
     val path = Path.explode(name.node)
     if (!path.is_file) error("No such file: " + path.toString)
-    f(File.read(path))
+
+    val text = File.read(path)
+    Symbol.decode_strict(text)
+    f(text)
   }