diff --git a/build/win/generate_winrt_headers.py b/build/win/generate_winrt_headers.py
index 81ada4c..3961612 100644
--- a/build/win/generate_winrt_headers.py
+++ b/build/win/generate_winrt_headers.py
@@ -44,7 +44,7 @@
     name = contract.getAttribute('name')
     version = contract.getAttribute('version')
     winmd_path = os.path.join(reference_dir, name, version, '%s.winmd' % name)
-    inputs.append(winmd_path)
+    inputs.append(os.path.realpath(winmd_path))
   return inputs