Topic Last Modified: 2007-01-17

The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine if the msExchESEParamMaxOpenTables attribute is present for any of the storage group objects under the InformationStore object of the Exchange Server object. If the Exchange Server Analyzer finds that the msExchESEParamMaxOpenTables attribute is present and configured, a non-default configuration message is displayed.

By default, for Exchange 2000 Server and Exchange Server 2003, this attribute is present but not set with any value. Exchange Server caches data about folders that are not currently being accessed. In some cases, this may contribute to virtual memory fragmentation. One way to mitigate this is to reduce the maximum number of database tables that can be open concurrently. The actual suggested value for this varies depending on the version of Exchange Server and the Exchange service pack that is installed. For Exchange 2000 Server Service Pack 2, the default setting for 8-processor servers is 85,000 tables per storage group. This is reduced to 27,600 in Exchange 2000 Server Service Pack 3 for 8-processor servers. For 4-processor servers, the value is 13,800. This value can be lowered to reduce virtual memory fragmentation issues. However, lowering this value could also cause situations where operations may fail because of too many open tables. The error occurs because the maximum number of tables that could be concurrently open is being lowered, which means the maximum is reached sooner.

Exchange Server 2003 uses a different method for caching data about folders that are not currently being accessed. Therefore, reducing the maximum number of open tables is neither necessary nor effective for reducing virtual memory fragmentation issues. This attribute should not be set on an Exchange Server 2003 server.

Unless you have been instructed by Microsoft Product Support Services to enter a value here, use the Active Directory Service Interfaces (ADSI) Edit tool to clear the value set on this attribute.

If you incorrectly modify the attributes of Active Directory objects when you use ADSI Edit, the LDP (ldp.exe) tool, or another Lightweight Directory Access Protocol (LDAP) version 3 client, you may cause serious problems. These problems may require that you reinstall Microsoft Windows Server™ 2003, Exchange Server 2003, or both. Modify Active Directory object attributes at your own risk.

To clear the msExchESEParamMaxOpenTables attribute value

  1. Open an Active Directory editor, such as ADSI Edit.

  2. Double-click the Configuration container, expand CN=Services, expand CN=Microsoft Exchange, and then expand CN=ExchangeOrganizationName.

  3. Expand CN=Administrative Groups, expand CN=AdministrativeGroupName, and then expand CN=Servers.

  4. Expand CN=ExchangeServerName, expand CN=InformationStore, right-click CN=StorageGroupName, and then click Properties.

  5. In the Select a property to view box, click msExchESEParamMaxOpenTables.

  6. In the Edit Attribute box, click Clear to change the value to <not set>.

  7. Click OK, and then click OK again.

  8. Close the Active Directory editor and restart the Microsoft Exchange Information Store service for the change to take effect.

For more information about this attribute, see the Microsoft Knowledge Base article 325044, "HOW TO: Troubleshoot Virtual Memory Fragmentation in Exchange 2003 and Exchange 2000" (

For more information about using the LDP tool, see the Knowledge Base article 260745, "XADM: Using the LDP Utility to Modify Active Directory Object Attributes" (