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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_UNCONFIRMED "
   title="UNCONFIRMED - 'SAXParseException: Attribute w:cstheme redefined' error upon certain changes to a DOCX"
   href="https://bugs.documentfoundation.org/show_bug.cgi?id=113790">113790</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>'SAXParseException: Attribute w:cstheme redefined' error upon certain changes to a DOCX
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>LibreOffice
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>5.4.3.2 release
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>UNCONFIRMED
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>critical
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>medium
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>filters and storage
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>libreoffice-bugs@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>baron@caesar.elte.hu
          </td>
        </tr>

        <tr>
          <th>Blocks</th>
          <td>104448
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="http://bugs.documentfoundation.org/attachment.cgi?id=137703" name="attach_137703" title="Sample DOCX">attachment 137703</a> <a href="http://bugs.documentfoundation.org/attachment.cgi?id=137703&action=edit" title="Sample DOCX">[details]</a></span>
Sample DOCX

I received a file that gave the same error message upon opening as <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Writer hangs after error message (SAXParseException: Attribute w:cstheme redefined) on invalid docx"
   href="show_bug.cgi?id=102929">bug 102929</a>
(that error is also mentioned in <a class="bz_bug_link 
          bz_status_NEEDINFO "
   title="NEEDINFO - Copy-pasting text from document body into comment breaks all following comments when saving to docx. Leads to duplicate attributes of comment, which breaks the parsing of all following comments."
   href="show_bug.cgi?id=92731">bug 92731</a>):
'SAXParseException: [word/document.xml line 2]: Attribute w:cstheme redefined.'

The erroneous element looked like this:
<w:rFonts w:cs="Calibri" w:cstheme="minorHAnsi" w:ascii="Calibri"
w:hAnsi="Calibri" w:cstheme="minorHAnsi"/>

After removing the duplicate attribute from the file manually, the document
could be opened. I copied the relevant part of the text to a new document,
simplified it, and managed to get the followiing repro case:
- Open the attached sample document.
- Copy the bulleted entry "ABCD", and paste it somewhere else, eg. above
"Title3".
- Save as a different DOCX, and reopen it.

=> You get the error/exception mentioned above.

Reproduced using LO 6.0 daily build (2017-11-06_23:18:19,
a5af0fd9f27af42cf2e8571f659cdad6e606215b), 5.4.3.2 / Windows 7.

Note that the sample file, as well as the fixed original contains a couple of
instances of the following OOXML validation error (no idea if it's related,
Word and Writer opens the documents fine):
NumberingSymbolRunProperties    /word/numbering.xml    
/w:numbering[1]/w:abstractNum[1]/w:lvl[1]/w:rPr[1]      RunFonts        The
element has unexpected child element</pre>
        </div>
      </p>

        <div id="referenced">
          <hr style="border: 1px dashed #969696">
          <b>Referenced Bugs:</b>
          <ul>
              <li>
                [<a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [META] DOCX SAXParseException"
   href="https://bugs.documentfoundation.org/show_bug.cgi?id=104448">Bug 104448</a>] [META] DOCX SAXParseException
              </li>
          </ul>
        </div>
        <br>

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      <ul>
          <li>You are the assignee for the bug.</li>
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