title: Why does Microsoft.Office.Interop.Excel.Application.Quit() leave the background process running?
body: <p>The following code leaves a Microsoft Excel background process running, until after my program has exited:</p>
  
  <pre><code>var excelApplication = new Application();
  var workbooks = excelApplication.Workbooks;
  var workbook = excelApplication.Workbooks.Open(file.FullName);
  
  workbook.Close();
  excelApplication.Workbooks.Close();
  excelApplication.Quit();
  
  Marshal.ReleaseComObject(workbook);
  Marshal.ReleaseComObject(workbooks);
  Marshal.ReleaseComObject(excelApplication);
  </code></pre>
  
  <p>Why? What am I missing?</p>