title: Using closedXML C# library, How can I figure out what data is causing this error when trying to save
body: <p>I have a C# app that exports to Excel using <a href="http://closedxml.codeplex.com/" rel="noreferrer">ClosedXML</a>.  It works fine but just ran into an issue where when i hit the :</p>
  
  <pre><code>  var ms = new MemoryStream();
    workbook.SaveAs(ms);
  </code></pre>
  
  <p>I get an exception:</p>
  
  <pre><code>' ', hexadecimal value 0x0B, is an invalid character
  </code></pre>
  
  <p>Its definitely data related because it I look at certain data it works fine but other data it causes this issue.</p>
  
  <p>how can i figure out which character is causing the issue?  Also, once I figure that out, what is the best way of finding where this character is within my data?</p>