diff --git a/dlls/itss/itss.spec b/dlls/itss/itss.spec
index a5e0c57fca1..7437ca82333 100644
--- a/dlls/itss/itss.spec
+++ b/dlls/itss/itss.spec
@@ -3,4 +3,4 @@
 @ stub DllInstall
 @ stdcall -private DllMain(long long ptr)
 @ stdcall -private DllRegisterServer()
-@ stub DllUnregisterServer
+@ stdcall -private DllUnregisterServer()