diff --git a/dlls/advapi32/tests/registry.c b/dlls/advapi32/tests/registry.c
index 32f391044c8..389fa25e31b 100644
--- a/dlls/advapi32/tests/registry.c
+++ b/dlls/advapi32/tests/registry.c
@@ -48,7 +48,7 @@ static DWORD delete_key( HKEY hkey )
         if (ret) break;
     }
     if (ret != ERROR_NO_MORE_ITEMS) return ret;
-    RegDeleteKeyA( hkey, NULL );
+    RegDeleteKeyA( hkey, "" );
     return 0;
 }