diff -r 3cee9d20308e -r e61add9d5b5e src/Pure/System/isabelle_system.scala
--- a/src/Pure/System/isabelle_system.scala	Thu Jul 08 13:16:31 2021 +0200
+++ b/src/Pure/System/isabelle_system.scala	Thu Jul 08 13:34:12 2021 +0200
@@ -153,7 +153,7 @@
   def make_directory(path: Path): Path =
   {
     if (!path.is_dir) {
-      try { Files.createDirectories(path.file.toPath) }
+      try { Files.createDirectories(path.java_path) }
       catch { case ERROR(_) => error("Failed to create directory: " + path.absolute) }
     }
     path