Symptoms

Exporting a Confluence page to word doesn't work after Confluence upgrade; it downloads the pages to HTML format instead due to .doc and .docx file formats are not supported.

The following appears in the atlassian-confluence.log:

20XX-XX-XX XX:XX:XX,XXX ERROR [http-80-17] [[Standalone].[localhost].[/].[exportword]] log Servlet.service() for servlet exportword threw exception
javax.activation.UnsupportedDataTypeException: no object DCH for MIME type multipart/related; 

Cause

Confluence is using incompatible Java version.

Resolution

1. Stop Confluence

2. Make sure Confluence is using supported Java version (Check for Confluence Supported Platform)
   Earlier versions of Confluence use Java version 1.6.x while Confluence 5.x and above use Java version 1.7.x

3. Make sure java.library.path points to the corresponding Java version.
   It is possible that users's Java version don't correspond to java.library.path, which can caused the issue to happen

4. Start Confluence