By using the Offline Address Book, Outlook does not have to connect to Exchange in order to resolve names or open the records for each user.
If Outlook is left running constantly in Cached Exchange Mode, it updates the Offline Address Book automatically about once a day, depending on Address Book updates on the server running Exchange.
This reduces network traffic and improves performance.
Therefore, not all the information in the GAL is available in the offline address book.
The following information in the GAL is not available in the offline address book: Outlook must be able to access Exchange to obtain this information.
If your users are running Office 2003, select Enable public folders distribution.
In this case the OAB will be distributed from a public folder of Exchange Server.
This article explains how to create a new Offline Address Book (OAB) on Exchange Server 2010.
The Offline Address Book is an offline copy of all the email addresses within Exchage Server.Therefore, if you are in Cached Exchange Mode and if you are working online — that is, your connection status is Connected to Microsoft Exchange — Outlook uses both the offline address book and the GAL to provide a complete listing of user information.If you are in Cached Exchange Mode and your connection status is Disconnected, Trying to Connect, or Offline, you can see only the information that is in the offline address book.The other day I was troubleshooting an issue where users were not able to download the Offline Address Book (OAB).After some troubleshooting steps, I ran the Outlook Auto Configuration Test and noticed that the URL for the OAB was not listed: To further test the OAB, beside manually downloading it in Outlook, you can write down the OAB URL, paste it into the address box in Windows Internet Explorer, add /to the end of the path, and then press Enter.The following Macs should therefore be able to run Office 2016 for Mac.