The msExchHomeMDB attribute is indexed

[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]  

Topic Last Modified: 2005-11-17

The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine whether the Routing Group Back-Link attribute has been configured for indexing in Active Directory. Specifically, the Exchange Server Analyzer queries Active Directory to determine the current indexing value for the msExchHomeMDB attribute, which is an attribute of mailbox-enabled objects in Active Directory. By default, this attribute is not indexed. If the Exchange Server Analyzer finds that this attribute is configured for indexing, a non-default configuration message is displayed.

The effect of having the msExchHomeMDB attribute indexed is minimal. There will be a small increase in the amount of memory used on global catalog servers because of maintaining the index in memory.

If any of the following apply to your organization, you may benefit from indexing this attribute:

  • You have many mail-enabled objects. In very large environments—those with 100,000 or more mail-enabled objects—indexing this attribute can also increase the performance of Exchange System Manager, as well as the Exchange-specific tasks that can be performed with Active Directory Users and Computers.

  • If you frequently use the Exchange Mailbox Merge Program (ExMerge), it has been found that indexing the msExchHomeMDB attribute is occasionally necessary in medium to large environments that use ExMerge. Indexing the msExchHomeMDB attribute has been shown to increase the speed and performance of ExMerge.

If neither of these situations applies, it is recommended that the setting be changed back to the default value of not indexed.

To correct this error

  • There is no action required, because the message generated by the Exchange Server Analyzer is for informational purposes only.