Office File Validation (OFV) is a security add-in for Office 2003 & 2007. It first introduced in Microsoft Office 2010. OFV for Microsoft Office 2003 & 2007 verifies that a particular binary file (such as .doc) complies with the application’s expectations. If files fail to conform to the format, user will be notified for possible security risks.
Download and install Microsoft OFV from Microsoft Download Center (supported OS are Windows 7, Windows Vista, & Windows XP).
Also make note of the following. To help protect your computer from security risks, try to avoid opening files received as email message attachment from unknown source/person.