This policy setting allows you to specify a location that is used as a trusted source for opening files in this application. ...

This policy setting allows you to specify a location that is used as a trusted source for opening files in this application.  Files in trusted locations bypass file validation, active content checks and Protected View. Macros and code in these files will execute without displaying warnings to the user. If you change or add a location make sure that the new location is secured, with only appropriate user permissions to add document/files.If you enable this policy setting, you may specify a folder location, path, and date from which files can the application can open files which run macros without warning. If you disable or do not configure this policy setting, the trusted location is not specified.