Information
This policy setting controls whether trusted locations on the network can be used. The recommended state for this setting is: Disabled. By default, files located in trusted locations and specified in the Trust Center are assumed to be safe. Content, code, and add-ins are allowed to load from trusted locations with minimal security and without prompting the user for permission. By default, users can specify trusted locations on network shares or in other remote locations that are not under their direct control by selecting the Allow Trusted Locations on my network (not recommended) check box in the Trusted Locations section of the Trust Center. If a dangerous file is opened from a trusted location, it will not be subject to typical security measures and could affect users' computers or data.
Solution
To implement the recommended configuration state, set the following Group Policy setting to Disabled. User Configuration\Administrative Templates\Microsoft Access 2013\Application Settings\Security\Trust Center\Trusted Locations\Allow Trusted Locations on the network Impact: Disabling this setting will cause disruption for users who add network locations to the Trusted Locations list. However, this practice is discouraged (as the Allow Trusted Locations on my network (not recommended) check box itself states), so in practice it should be possible to disable this setting in most situations without causing significant usability issues for most users.