InformationThis policy setting controls whether the specified Office application notifies users when unsigned application add-ins are loaded or silently disable such add-ins without notification. This policy setting only applies if you enable the 'Require that application add-ins are signed by Trusted Publisher' policy setting, which prevents users from changing this policy setting. The recommended state for this setting is: Enabled. By default, if an application is configured to require that all add-ins be signed by a trusted publisher, any unsigned add-ins the application loads will be disabled and the application will display the Trust Bar at the top of the active window. The Trust Bar contains a message that informs users about the unsigned add-in.
SolutionTo implement the recommended configuration state, set the following Group Policy setting to Enabled. User Configuration\Administrative Templates\Microsoft Access 2013\Application Settings\Security\Trust Center\Disable Trust Bar Notification for unsigned application add-ins and block them Impact: This setting only applies if the Office application is configured to require that all add-ins are signed by a trusted publisher. By default, users can configure this requirement themselves in the Add-ins category of the Trust Center for the application. To enforce this requirement, you must enable the Require that application add-ins are signed by Trusted Publisher setting in Group Policy, which prevents users from changing the setting themselves.