Directory and Resource Administrator 7.x
Exchange system mailbox accounts are visible in Directory and Resource Administrator.
System accounts are visible in DRA, but I did not select Show advanced Active Directory objects.
If Show advanced Active Directory objects is not selected under Administration Server Options, Directory and Resource Administrator (DRA) does not show hidden system containers, such as Exchange System Objects. However, DRA does not prevent the individual objects in the containers, such as Exchange system mailboxes, from being displayed if searches are performed at the domain level with an account, such as a DRA administrator, that has permissions over user accounts in the domain.
To prevent Exchange system mailboxes from being visible to Assistant Administrators, create ActiveViews for only those OUs or Containers that the Assistant Admin manages.