Shortly after the release of the October Public Update, we received notification of a potential issue affecting Office 2010 and Office 2013 users. In some cases, users running Office 2013 or Office 2010 may not be able update Microsoft Word fields in a few scenarios after the October Public updates are installed. We have since corrected the issue in Office 2013 Click-to-Run build 15.0.4675.1002. For Office 2010 and Office 2013 MSI users, please see the following updates to correct the issue.
Office 2013 - http://support.microsoft.com/kb/2920738
Office 2010 - http://support.microsoft.com/kb/2920807