title: OpenXML PowerPoint files won't open on IOS 7 devices
body: <p>Similar to <a href="https://stackoverflow.com/questions/10929054/openxml-spreadsheet-created-in-net-wont-open-in-ipad">this question</a>, I was having trouble opening OpenXML 2.5 documents on my iPad. After some trial and error, I found this xml tag:</p>
  
  <blockquote>
    <p>&lt; Override PartName="/ppt/presentation.xml" ContentType="application/vnd.openxmlformats-officedocument.presentationml.presentation.main+xml" /></p>
  </blockquote>
  
  <p>needs to be present in the <code>"[Content_Types].xml"</code> file in the root of the .pptx file (which is really just a zip archive). Then the file can be opened in both PowerPoint on the PC (tested on version 2010) and IOS 7.</p>