Hi, I have a .exe and .dll installed on Windows Server 2003 for use by thin clients using Terminal Services. The thin client user logs into Lotus Notes (which is running on the Server) which calls the .dll which runs the .exe and passes the .exe a structure. The .exe, amongst other things, tries to read and then write several keys to both the HKey Local Machine and HKey Current User and this is where the problem lies. The .exe only works when the thin client is given Admin privileges to the Server; otherwise Firstly, the .exe doesn't seem to find the Local Machine Keys (if not also the Current User keys) when the .exe loads. Secondly, the .exe it exits with the following message when it tries to write to registry keys: System.UnauthorizedAccessException: Access to the registry key is denied. at Microsoft.Win32.RegistryKey.Win32Error(Int32 errorCode, String str) at Microsoft.Win32.RegistryKey.SetValue(String name, Object value) All Thin client users have been given permission to read and write to the Local Machine and Current User keys. The .exe works on Windows machines under the same scenario (called from inside Lotus Notes which calls the .dll which runs the .exe etc.) whether the user has Admin privileges or not. Any ideas? Many thanks, _______________________________________________ Kirsten Mayer Software Developer E: kmayer@xxxxxxxxxx