I am trying to start a process as the LocalSystem account using this code ProcessStartInfo _startInfo = new ProcessStartInfo(commandName); _startInfo.UseShellExecute = false; _startInfo.UserName = @"NT AUTHORITY\SYSTEM"; _startInfo.CreateNoWindow = true; _startInfo.Arguments = argument; _startInfo.RedirectStandardOutput = true; using (Process _p = Process.Start(_startInfo)) { _retVal = _p.StandardOutput.ReadToEnd(); _p.WaitForExit(); } But I am getting always the same error message saying "Logon failure: unknown user name or bad password". The user calling the function is a local admin and should be able to start a process with local system privilege. I also tried different combination but no luck. I would appreciate any help. Thanks