I am trying to create an offline registry in memory using the offreg.dll provided in the windows ddk 7 package. You can find out more information on the offreg.dll here: MSDN Currently, while attempted to create the hive using ORCreateHive, I receive the following error: "Managed Debugging Assistant 'PInvokeStackImbalance' has detected a problem. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature." Here is the offreg.h file containing ORCreateHive: typedef PVOID ORHKEY; typedef ORHKEY *PORHKEY; VOID ORAPI ORGetVersion( __out PDWORD pdwMajorVersion, __out PDWORD pdwMinorVersion ); DWORD ORAPI OROpenHive ( __in PCWSTR lpHivePath, __out PORHKEY phkResult ); DWORD ORAPI ORCreateHive ( __out PORHKEY phkResult ); DWORD ORAPI ORCloseHive ( __in ORHKEY Handle ); The following is my C# code attempting to call the .dll and create the pointer for future use. using System.Runtime.InteropServices; namespace WindowsFormsApplication6 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } [DllImport("offreg.dll", CharSet = CharSet.Auto, EntryPoint = "ORCreateHive", SetLastError=true, CallingConvention = CallingConvention.StdCall)] public static extern IntPtr ORCreateHive2(); private void button1_Click(object sender, EventArgs e) { try { IntPtr myHandle = ORCreateHive2(); } catch (Exception r) { MessageBox.Show(r.ToString()); } } } } I have been able to create pointers in the past with no issue utilizing user32.dll, icmp.dll, etc. However, I am having no such luck with offreg.dll. Thank you.