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Manually deploy offline address book files

Office 2010

Applies to: Office 2010

Topic Last Modified: 2012-01-27

To minimize performance issues, you can manually deploy offline address book (OAB) files to remote client computers.

You can manually deploy OAB files to remote client computers by using web-based distribution. The remote client computers run Microsoft Outlook 2010 in Cached Exchange Mode and they are connected to a computer that is running Microsoft Exchange Server.

In this article:

When Outlook is used with Exchange Server, Outlook uses the OAB to provide offline access to directory information from the global address list (GAL) when users work offline or are configured to use Cached Exchange Mode. When a user starts Outlook in Cached Exchange Mode for the first time, the user's Exchange mailbox is synchronized to a local offline folder (.ost) file. The offline address list from the Exchange Server is typically synchronized to a collection of OAB files on the user's computer.

This synchronization can cause performance issues with Exchange Server, or the organization's Network topology, or both. The significance of the issues depends on the size of the user’s mailbox, the size of the organization's GAL, the number of people who are using Outlook 2010 in Cached Exchange Mode, and the network bandwidth. During an initial synchronization with the Exchange Server, remote users may experience delayed responses during the initial synchronization of Outlook 2010 with the server.

In environments that have low bandwidth or unreliable connections, a manual deployment of the OAB might minimize the length of initial synchronization for remote Outlook 2010 users and the number of performance issues on Exchange Server.

To manually deploy an OAB, you must first generate the OAB on a test computer by deleting the existing OAB files and resynchronizing the OAB files for that OAB from the computer that is running Exchange Server. Then, to deploy the OAB, you copy the subfolders in the Offline Address Book folder from the test computer to the remote computer. Finally, you export the OAB registry subkeys from on the test computer and import them to the remote computer.

Some organizations might have multiple OABs that have been generated from different Exchange mailbox servers. Each OAB has a Globally Unique Identifier (GUID). When generating the OAB that you want to deploy to the remote computers, verify that the OAB contains the offline address lists that you want. In Windows Explorer, navigate to the Offline Address Book folder. In this folder, you will find one or more OAB folders titled with the GUID. If you have multiple OABs, you must note the GUID for the OAB that you want to deploy and verify that you import the registry subkeys for that OAB to the remote computers. The OAB registry subkeys are stored under the GUID for that OAB.

The OAB folder contains six files for a full-details OAB or five files for a no-details OAB. The file names determine whether the OAB is in Unicode format or in ANSI format (Unicode format files begin with a "U"). The following table lists the file names that are included.


Unicode ANSI Notes







This file is not present in a no-details OAB.







By default, Outlook 2010 downloads Unicode OAB files.

For more information about OABs, see Exchange 2010 Help: Understanding Offline Address Books (

Locate a test computer that you can use to generate the OAB files that you want to deploy. Then, if multiple OABs have been generated in the Exchange environment, determine the one that you want to deploy to the remote computers.

Follow the steps in these procedures to generate and manually deploy the OAB files to remote client computers.

To generate the offline address book files
  1. Delete the *.oab files that are on the test computer. By default, the *.oab files are located in subfolders in the following Outlook folders:

    In Windows 7 or Windows Vista: \Users\<username>\AppData\Local\Microsoft\Outlook\Offline Address Books

    In Windows XP: \Documents and Settings\<username>\Local Settings\Application Data\Microsoft\Outlook\Offline Address Books

  2. Create a new Outlook profile that uses Cached Exchange Mode on the test computer. For more information about Cached Exchange Mode, see Configure Cached Exchange Mode in Outlook 2010.

  3. Start Outlook 2010 with this new profile.

  4. In the ribbon click Send / Receive, click Send/Receive Groups and then click Download Address Book.

  5. In Windows Explorer, locate the following folder:

    In Windows 7 or Windows Vista: \Users\<username>\AppData\Local\Microsoft\Outlook\Offline Address Books

    In Windows XP: \Documents and Settings\<username>\Local Settings\Application Data\Microsoft\Outlook\Offline Address Books

  6. If you plan to use portable media to send to remote users, examine the size of all OAB files that are in this folder and its subfolders. Make sure that all OAB files fit on the portable media.

  7. Copy the subfolders and files in this directory to your distribution media.

To deploy the offline address book files
  1. On the remote client computer, copy the directories that contain the *.oab files that you generated in the To generate the offline address book files section to the following folder:

    In Windows 7 or Windows Vista: \Users\<username>\AppData\Local\Microsoft\Outlook\Offline Address Books

    In Windows XP: \Documents and Settings\< user name>\Local Settings\ Application Data\Microsoft\Outlook\Offline Address Books\

    For information about how to export and import registry subkeys, follow the instructions in the Microsoft Knowledge Base article 310516: How to add, modify, or delete registry subkeys and values by using a registration entries (.reg) file (
  2. From the test computer that you used to generate the OAB files, export the appropriate OAB GUID registry subkeys from the following path:

    HKEY_CURRENT_USER\Software\Microsoft\Exchange\Exchange Provider\OABs

  3. On the client computer, import the registry subkeys.

  4. Start Outlook 2010 on the remote client computer.

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