title: extract xlsx file with phpspreadsheet doesn't work
body: <p>I have a specific xlsx file auto-generated by a sport performance monitoring tool.</p>
  
  <p><a href="http://bruet.iiens.net/Excel/ExtractExcelProblem.xlsx" rel="nofollow noreferrer">An example of this file</a></p>
  
  <p>To extract data on my file, I use the <a href="https://github.com/PHPOffice/PhpSpreadsheet" rel="nofollow noreferrer">PhpSpreadsheet</a> class.</p>
  
  <p>This is my code :</p>
  
  <pre><code>$reader = new \PhpOffice\PhpSpreadsheet\Reader\Xlsx();
  $reader-&gt;setReadDataOnly(true);
  $spreadsheet = $reader-&gt;load($this-&gt;filePath);
  
  $spreadsheet = $reader-&gt;load($this-&gt;filePath);
  $value = $spreadsheet-&gt;getSheetNames();
  var_dump($value);
  </code></pre>
  
  <p>Normaly this code should give output of 2 names in the sheet : ['Données', 'Résultats']</p>
  
  <p>But the code output : <code>array(1) { [0]=&gt; string(9) "Worksheet" }</code></p>
  
  <p>It's an empty file.</p>
  
  <p>The weird thing is if I open the file with Excel Program and I save the file without making no modifications, my code output the right sheet names..</p>
  
  <p><strong>Has anyone encountered this problem ?</strong></p>