If you’ve recently stumbled upon or have been emailed a document with the .docx extension, you’ve probably been wondering what it is and what you can view it with.

Well it turns out that DOCX is the new document format for Microsoft Word 2007. The big problem is that this type of document is not compatible with older versions of Microsoft Word, so you’ll find that even if you have Microsoft Word (earlier than 2007 version) installed, you won’t be able to open your file. You could resort to one of the websites that do or claim to convert DOCX documents to DOC files readable by Microsoft Word 2003 and older, but the best solution is to use a compatibility pack offered by Microsoft which updates your Word installation with the necessary components. It’s as easy as downloading the update pack and running it. You can download this package here.