When contacts are added to an organizations Global Address List (GAL), they do not always populate in the users personal device contacts depending on what app, device, etc. is being used. This becomes problematic when users working from outside the office are unable to contact the IT Service Desk, HR, or other internal services. To solve the problem, this article introduces a PowerShell script that will read a set of standard contacts from a CSV file and write them as personal contacts to user mailboxes. Mobile devices can then synchronize these contacts along with others created by the user.
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.