Problem

   Message with a .docx attachment that is less than 20 MB exceeds 100 MB size limit on decomposition. Is there a way to validate why this happens?

Resolution

   In order to check this, you can simply extract the docx file with your favorite archive tool (in this article we will use 7-Zip - an open source Windows utility for manipulating archives). Right-click on the docx file, go over 7-Zip and select ExtractTo "<folder>", take a look at the size of the folder and explore the sub-folders and content.

   The significant expanding of the file in size after decomposition, is due to the fact that MS Office 2007 (or later) files (like docx, xlsx, etc.) are XML based archives.

Related pages:

• MS Office XML based files:   http://msdn.microsoft.com/en-us/library/office/aa338205%28v=office.12%29.aspx
• 7Zip:   http://www.7-zip.org/