diff --git a/PInvoke/Security/AdvApi32/PSID.cs b/PInvoke/Security/AdvApi32/PSID.cs
index 1f80926a..1c6f6898 100644
--- a/PInvoke/Security/AdvApi32/PSID.cs
+++ b/PInvoke/Security/AdvApi32/PSID.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Linq;
 using System.Runtime.InteropServices;
 using Vanara.Extensions;
 using Vanara.InteropServices;