This policy setting allows you to block macros from running in Office files that come from the Internet.
If you enable this policy setting, macros are blocked from running, even if "Enable all macros" is selected in the Macro Settings section of the Trust Center. Also, instead of having the choice to "Enable Content," users will receive a notification that macros are blocked from running. If the Office file is saved to a trusted location or was previously trusted by the user, macros will be allowed to run.
If you disable or don't configure this policy setting, the settings configured in the Macro Settings section of the Trust Center determine whether macros run in Office files that come from the Internet.