Offline Address Book Generation/Update

The OAB is used for Cached/Offline mode clients to perform lookups of contacts and other information. It is periodically updated from the Exchange Server to Outlook clients. A complete overview of how the OAB works in various versions of Exchange can be found on Microsoft TechNet by searching the sections for your specific version of Exchange.

In earlier versions of Exchange Server, a Public Folder was used to house the OAB data and distribute it. In 2007 and 2010, a web-based distribution system was put in place, with the ability to also maintain a Public Folder version in the event you have legacy Outlook (2003 SP1 or earlier) clients. While distribution of the OAB to any Outlook client is fairly automatic, the generation of the OAB for the first time may not fit into your time tables.

Usually, the OAB will update as part of the Online Maintenance Routines that occur by default every day from 1am to 3am server local time. This means that the OAB will not be generated at all until that first maintenance window, and will not be updated with new users until the first maintenance window after they are added to AD. There are several reasons why this may not work for you, but some common ones are:

- You’ve added a VIP to the AD system and management doesn’t want to wait 24 hours for the OAB to update.

- You have created a test system, and either don’t want to leave the system running overnight, or need to perform testing within the first 24 hours of the build.

- You add a large number of users to AD, and want to propagate the information to Outlook clients as quickly as possible.

In these, and other cases, you could force the Online Maintenance to occur, but that would take a significant amount of time, especially if all you want to do is update the OAB. In a production environment, performing maintenance routines during peak hours of operations can also have an impact on user experience, and so should be avoided.

To perform an immediate update of the just the OAB in Exchange Server 2007 or 2010, you can open a PowerShell command window and execute the following:

Update-OfflineAddressBook –id “Name of OAB” –verbose

Where “Name of OAB” is the name of the Offline Address Book you wish to update. Be sure to enclose it in quotes, especially if the name contains spaces. The default OAB for a new installation of Exchange is – oddly enough – “Default Offline Address Book” and you can use that name to perform the initial update on a brand new server.

If you maintain more than one OAB, or if you changed the default name, you must run the command for each OAB in your organization, replacing the name with the appropriate string each time.

The next time Outlook clients look for OAB information, they will see that the OAB has been updated, and download the appropriate changes to their local OAB copy.

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