title: Excel Interop Workbooks.Open inconsistencies
body: <p>I have a process that is opening multiple workbooks </p>
  
  <pre><code>var exApp = new Excel.Application(); 
  Excel.Workbook ONE;
  Excel.Workbook TWO;
  Excel.Workbook THREE;
  ONE = exApp.Workbooks.Open(ONELocation);
  TWO = exApp.Workbooks.Open(TWOLocation);
  THREE = exApp.Workbooks.Open(THREELocation);
  Console.WriteLine("All Excel workbooks opened successfully\n");
  </code></pre>
  
  <p>Sometimes it runs with no issues. </p>
  
  <p>Sometimes though I get the following exception on crash</p>
  
  <blockquote>
    <p>System.Runtime.InteropServices.COMException: 'The remote procedure call failed. (Exception from HRESULT: 0x800706BE)'</p>
  </blockquote>
  
  <p>The exception happens on different workbooks and sometimes not at all. When it happens after rerunning a few times the process goes through successfully and all data is processed correctly. </p>
  
  <p>Why does it work sometimes and not others? Is there a better way to open these workbooks? How do I stop this from happening?</p>