en Passant not letting life just pass on by

When running through the latest version of the Exchange calendar update process, it has you assign permissions to all mailboxes on the server. To modify all the mailboxes, you need to provide a list of distinguished names (DN) for each mailbox. Unfortunately this is not simply the DistiguishedName field that you would query from AD, but the LegacyDN entry. You need to query the Exchange environment to get this information.