ERROR 0x80030309 is a code that may pop up while using Microsoft Office. This error occurs when the font “Microsoft Sans Serif” does not exist on your computer, but has been embedded into the document you are opening. To fix this problem, download and install the correct font by visiting: http://www.microsoft.com/downloads/SearchResults.aspx?Category=&DisplayLang=en

EG: If you have version 2007 of MS Word installed, download the “Office Open XML File Extension Converter Tool for 2007”.  If you have version 2010 of MS Word installed, download the version labeled “Word Viewer AND Office Compatibility Pack SP2”. The specific links for these downloads can be found on the website.

After you have downloaded and installed the correct font, restart your computer and re-open the document that was giving you problem after choosing to replace or not replace the old font with new one.   You should now be able to use the document.

Restart your computer and then open this file again by pressing CTRL+O to choose either “Replace” or “Not Replace”. You can press ESCAPE if you change your mind about changing the font later on as well.  If an error message pops up saying “File not found” when you try to open the document again, you may need to download and install new fonts.  

After following the procedures to try and open your file, you will be able to use Microsoft Office again without any problems.