diff --git a/reactos/w32api/include/dsound.h b/reactos/w32api/include/dsound.h
index 6c1b05f82e4..36f3844c654 100644
--- a/reactos/w32api/include/dsound.h
+++ b/reactos/w32api/include/dsound.h
@@ -412,6 +412,7 @@ extern HRESULT WINAPI GetDeviceID(LPCGUID lpGuidSrc, LPGUID lpGuidDest);
 /*****************************************************************************
  * IDirectSound interface
  */
+#undef INTERFACE
 #define INTERFACE IDirectSound
 DECLARE_INTERFACE_(IDirectSound,IUnknown)
 {