title: Trying to read a TDMS file using python but I get a "check whether the tdm_index matches the file" error
body: <p>When I run this code:</p>
  <pre><code>from nptdms import TdmsFile as tf 
  file = tf('myfile.tdms')
  </code></pre>
  <p>I get the following error:</p>
  <blockquote>
  <p>&quot;Check that the tdms_index file matches the tdms data file.&quot;)</p>
  <p>ValueError: Attempted to read data segment at position 123 but did not
  find segment start header. Check that the tdms_index file matches the
  tdms data file.</p>
  </blockquote>
  <p>What am I doing wrong and what do I need to change?</p>