This policy setting controls whether to require that encrypted macros in Open XML presentations be scanned with antivirus software before being opened.
If you enable this policy setting, PowerPoint 2007 disables encrypted macros until they are scanned for viruses.
If you disable this policy setting, PowerPoint 2007 will not require encrypted macros to be scanned before loading. PowerPoint will handle them as specified by the 2007 Office System macro security settings.
If you do not configure this policy setting, the behavior is equivalent to Enabled.