OAB Bandwidth Threshold (KBps) registry parameter is non-default

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at http://go.microsoft.com/fwlink/?linkid=34707.]  

Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool reads the following registry key to determine whether the OAB Bandwidth Threshold (KBps) registry key has been created:


If the Exchange Server Analyzer finds that the OAB Bandwidth Threshold (KBps) registry key has been created under ParametersSystem, the Exchange Server Analyzer displays a non-default configuration message.

In Microsoft Exchange Server 2003 Service Pack 1 (SP1), the administrator can set and configure the OAB Bandwidth Threshold (KBps) registry key to override the default functionality and to limit the bandwidth that is used for full downloads of an offline address book from a particular public store.

By default, every client request for a full download of an offline address book is served immediately. Also, the public store does not limit the number of concurrent full downloads of offline address books. The Exchange Server Analyzer reports this configuration for informational purposes only. No action is required. However, you can delete the OAB Bandwidth Threshold (KBps) registry key if you want to restore the default configuration.


This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore the registry if a problem occurs. For information about how to restore the registry, view the "Restore the Registry" Help topic in Regedit.exe or Regedt32.exe.

To restore the default configuration

  1. Open a registry editor, such as Regedit.exe or Regedt32.exe.

  2. Navigate to: HKLM\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem

  3. Delete the OAB Bandwidth Threshold (KBps) value.

  4. Close the registry editor.

The Microsoft Exchange Information Store service detects the changes in minutes. You do not have to restart the computer.

Before you edit the registry, and for information about how to edit the registry, see the Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows Registry" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=256986).

For more information about throttling the bandwidth consumed during offline address book downloads, see the Knowledge Base article 867623, "Throttling full offline Address Book downloads to limit the effect on a LAN in Exchange Server 2003," (http://go.microsoft.com/fwlink/?linkid=3052&kbid=867623).