title: Some or all identity references could not be translated
body: <p>I want to set some access rules to a file. Now when i set the rule, the variable <code>name</code> contains the right username (like: domain\user).</p>
  
  <pre><code>string name = new SecurityIdentifier(rule.IdentityReference.Value).Translate(typeof(NTAccount)).ToString();
  accessControl.AddAccessRule(rule);
  </code></pre>
  
  <p>But the next line throws a IdentityNotMappedException with the message: </p>
  
  <blockquote>
    <p>Some or all identity references could not be translated.</p>
  </blockquote>
  
  <p>why I can translate in the first line the IdentityReference to a username, but the second line can't translate it?</p>