Can MS Office Protected View be Disabled via GPO?
The Protected View settings are specific to each application in Office (Word, Excel and Powerpoint only), and to each year (2010 and 2013 only).
Grab the ADMX templates, install them to the PolicyDefinitions folder for the domain, or add them individually to a GPO in Group Policy Management.
The settings are in: User Configuration, Policies, Administrative templates, Microsoft $PRODUCT $YEAR, $PRODUCT Options, Security, Trust Center, Protected View, "Do not open files in unsafe locations in Protected View", Enable.