title: Could not be converted to a type library - Error: Element not found
body: <p><sub>
  <em>NOTE: I am answering my own question in the event it helps others in the future.</em></sub></p>
  
  <p>I'm getting the error:</p>
  
  <blockquote>
    <p>The assembly "C:\XYZ.dll" could not be converted to a type
    library. Type library exporter encountered an error while processing
    'XYZ'. Error: Element not found.</p>
  </blockquote>
  
  <p>Here is the code that causes the problem:</p>
  
  <pre><code>[Guid("7a4e9867-96a7-43f0-9492-0327b9053853"),
  ClassInterface(ClassInterfaceType.None)]
  public class TimeSeriesPoint
  {
      public string Date { get; set; }
      public float Value { get; set; }
  }
  
  [Guid("7a4e9867-96a7-43f0-9492-0327b9053853"),
  InterfaceType(ComInterfaceType.InterfaceIsDual)]
  public interface IDataHelper
  {
      //RCOMServerLib.IStatConnector Connector { set; }
      string Text { set; }
      void DoCallback();
  </code></pre>