diff --git a/jps/jps-builders/src/org/jetbrains/jps/javac/JavacFileManager.java b/jps/jps-builders/src/org/jetbrains/jps/javac/JavacFileManager.java
index deb381e7d9e2..6e8682e1838b 100644
--- a/jps/jps-builders/src/org/jetbrains/jps/javac/JavacFileManager.java
+++ b/jps/jps-builders/src/org/jetbrains/jps/javac/JavacFileManager.java
@@ -100,7 +100,11 @@ class JavacFileManager extends ForwardingJavaFileManager<StandardJavaFileManager
     if (a instanceof OutputFileObject || b instanceof OutputFileObject) {
       return a.equals(b);
     }
-    return super.isSameFile(a, b);
+    return super.isSameFile(unwrapFileObject(a), unwrapFileObject(b));
+  }
+
+  private static FileObject unwrapFileObject(FileObject a) {
+    return a instanceof TransformableJavaFileObject ? ((TransformableJavaFileObject)a).getOriginal() : a;
   }
 
   @Override