title: File corruption while writing using Pandas
body: <p>I am reading data from a perfectly valid <code>xlsx</code> file and processing it using Pandas in Python 3.5. At the end I am writing the final dataframe to an Excel file using : </p>
  
  <pre><code>writer = pd.ExcelWriter(os.path.join(DATA_DIR, 'Data.xlsx'), 
  engine='xlsxwriter', options={'strings_to_urls': False})
  manual_labelling_data.to_excel(writer, 'Sheet_A', index=False)
  writer.save()
  </code></pre>
  
  <p>While trying to open the <code>Data.xlsx</code>, I am getting the error : <strong>We found a problem with some content in 'Data.xlsx'</strong>... On proceeding the file loads into Excel with info : <strong>Removed Records: Formula from /xl/worksheets/sheet1.xml part</strong></p>
  
  <p>I cannot find out what the problem is. </p>