Topic Last Modified: 2006-03-30

The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to obtain the count of objects in the directory that have an objectCategory of msExchExchangeServer. The count represents the number of Exchange Server computers found in Active Directory. If the Exchange Server Analyzer finds more than 900 Exchange Server computers, a warning is displayed.

It is recommended that you use a maximum of 900 instances for any single Exchange object type. This is because Active Directory defaults to 1,000 as the maximum page size that it returns for any given request. This means that if a Lightweight Directory Access Protocol (LDAP) request is made for an object, and more than 1,000 instances of that object exist in Active Directory, no results will be returned because the maximum page size is exceeded.

In the case of Exchange Server, various processes request instantiation of specific object types. For example, Exchange System Manager makes an LDAP request to Active Directory to create a list view of all Exchange servers within the Exchange organization. If there are more than 1,000 Exchange servers, Active Directory will not return any results. As a result, an error is displayed in Exchange System Manager and no Exchange Server computers are displayed.

Although the maximum page size value for Active Directory can be increased, this is not recommended or supported for Exchange. Odd behavior and failures have been exposed in Exchange environments where the maximum page size value has been increased.

Although the recommendation is to remain at or below 900 for any single object type in Exchange Server, up to 1,000 object types are supported.

To correct this warning

  1. Consider consolidating Exchange servers in your organization.

  2. Examine Active Directory for orphaned Exchange Server computers, and remove them from Active Directory.

For more information about consolidating Exchange servers, see "Server Consolidation Using Exchange Server 2003" (