diff --git a/reactos/include/ddk/portcls.h b/reactos/include/ddk/portcls.h
index ce818e1e99c..a2472cd7d75 100644
--- a/reactos/include/ddk/portcls.h
+++ b/reactos/include/ddk/portcls.h
@@ -1074,10 +1074,13 @@ typedef IPort *PPORT;
 */
 
 DEFINE_GUID(IID_IPortMidi,
-    0xb4c90a24L, 0x5791, 0x11d0, 0x86, 0xf9, 0x00, 0xa0, 0xc9, 0x11, 0xb5, 0x44);
+    0xb4c90a40L, 0x5791, 0x11d0, 0x86, 0xf9, 0x00, 0xa0, 0xc9, 0x11, 0xb5, 0x44);
 DEFINE_GUID(CLSID_PortMidi,
     0xb4c90a43L, 0x5791, 0x11d0, 0x86, 0xf9, 0x00, 0xa0, 0xc9, 0x11, 0xb5, 0x44);
 
+#undef INTERFACE
+#define INTERFACE IPortMidi
+
 DECLARE_INTERFACE_(IPortMidi, IPort)
 {
     DEFINE_ABSTRACT_UNKNOWN()