diff --git a/mediapipe/tasks/cc/core/external_file_handler.h b/mediapipe/tasks/cc/core/external_file_handler.h
index 3150fde59..01352df7f 100644
--- a/mediapipe/tasks/cc/core/external_file_handler.h
+++ b/mediapipe/tasks/cc/core/external_file_handler.h
@@ -82,9 +82,11 @@ class ExternalFileHandler {
 
   // The aligned mapped memory buffer offset, if any.
   int64 buffer_aligned_offset_{};
+#ifndef _WIN32
   // The aligned mapped memory buffer size in bytes taking into account the
   // offset shift introduced by buffer_aligned_memory_offset_, if any.
   int64 buffer_aligned_size_{};
+#endif
 };
 
 }  // namespace core