Assume that there are lots of Offline Address Books (OABs) in a Microsoft Exchange Server 2007 environment. In this scenario, the W3WP.exe process in the Autodiscover application pool consumes excessive CPU resources on the Exchange Server 2007 Client Access servers. Therefore, the Autodiscover service is almost unresponsive, and lots of users cannot connect to the Exchange Server 2007 servers.
To resolve this issue, install the following update rollup:
2509911 Description of Update Rollup 4 for Exchange Server 2007 Service Pack 3
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about the Autodiscover service, visit the following Microsoft website: