How to diagnose an issue in which an Exchange recipient that is visible in the GAL may not appear in the offline address book.
Some end users in your Exchange Server environment may have a requirement to “send as” a mailbox that they also need to remain hidden from the global address list.
You may encounter an issue where the emails that end users receive show the SMTP address of the sender instead of the more friendly display name configured on the user mailbox that has that SMTP address.
In this tutorial I show you how to use recipient filters to exclude Mail User objects from a Global Address List.
How to modify the recipient filter of the default Global Address List in an Exchange Server 2010 organization.