This policy setting controls whether the specified Office 2013 applications notify 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.
If you enable this policy setting, applications automatically disable unsigned add-ins without informing users.
If you disable this policy setting, 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.
If you do not configure this policy setting, the disable behavior applies, and in addition, users can configure this requirement themselves in the ''Add-ins'' category of the Trust Center for the application.