diff --git a/reactos/include/psdk/t2embapi.h b/reactos/include/psdk/t2embapi.h
index e584a1239a6..12a010db14c 100644
--- a/reactos/include/psdk/t2embapi.h
+++ b/reactos/include/psdk/t2embapi.h
@@ -38,6 +38,8 @@
 #define E_NONE 0x0
 #endif
 
+#define E_API_NOTIMPL 0x0001L
+
 #ifndef E_CHARCODECOUNTINVALID
 #define E_CHARCODECOUNTINVALID     0x2
 #define E_CHARCODESETINVALID       0x3