True or False: Only empty groups can be deleted in Mimecast.

The statement that only empty groups can be deleted in Mimecast is true. In the context of Mimecast, an empty group refers to a group that does not contain any members. The system’s restriction on group deletion is designed to maintain the integrity of configurations, as deleting a group that is being used in policies could disrupt various functions or lead to inconsistencies within the management system. Thus, allowing only empty groups to be deleted ensures that users have a clean and manageable directory structure without the risk of removing groups that could still have significant implications in terms of policies or assignments.

The other choices suggest various scenarios under which a group could be deleted, but they do not align with Mimecast's approach to group management. For instance, even if a group is not used in any policies, it may still have members that prevent deletion, reinforcing the need to ensure a group is entirely empty before it can be removed from the platform.