Topic Last Modified: 2010-02-15

The Microsoft Exchange Server 2010 Management Pack for System Center Operations Manager monitors the Windows Application log on computers running Exchange 2010 and generates this alert when the events specified in the following Details table are logged.

To learn more about this alert, in Operations Manager, do one or more of the following:


Product Name


Product Version

14.0 (Exchange 2010)

Event ID


Event Source

MSExchange ADAccess

Alert Type


Rule Path

Microsoft Exchange Server/Exchange 2010/Common Components/Active Directory Access

Rule Name

A request to establish a connection between the Exchange Active Directory Provider and a domain controller failed. The domain controller isn't available.


This Error event indicates that the domain controller specified in the event description is not working or not reachable. The Active Directory provider maintains a pool of connections to the available domain controllers. Any Exchange process that has to access Active Directory uses an available connection from the connection pool. This event may occur if the connection in the connection pool indicates that the domain controller is not working or not reachable. 

User Action

To resolve this error, do the following:

  1. Make sure that the domain controller is running and operational. Do one or more of the following:

    • Review the Application log for MSExchangeADAccess Event ID 2150. Event ID 2150 provides more information about the available domain controllers, global catalog servers, and configuration domain controllers in the Active Directory provider connection pool.

    • Use the Ping or PathPing command-line tools to test basic connectivity. Use Ping to isolate network hardware problems and incompatible configurations. Use PathPing to detect packet loss over multiple-hop trips. For more information, see Microsoft Knowledge Base article 325487, How to troubleshoot network connectivity problems.

    • Run the Dcdiag command-line tool to test domain controller health. To do this, run dcdiag /s:<Domain Controller Name> at a command prompt on the Exchange server. Use the output of Dcdiag to discover the root cause of any failures or warnings that it reports. For more information, see Dcdiag Overview at the Windows Server TechCenter.

  2. After you make sure that the domain controller specified in the event description is running, restart the Active Directory topology service to rebuild the connection pool.

If this error persists, review the Application log and System log on the domain controller and Exchange server for any corresponding Warning or Error events.

For More Information

If you are not already doing so, consider running the Exchange tools created to help you analyze and troubleshoot your Exchange environment. These tools can help make sure that your configuration aligns with Microsoft best practices. They can also help you identify and resolve performance issues, improve mail flow, and better manage disaster recovery scenarios. To run these tools, go to the Toolbox node of the Exchange Management Console. To learn more about these tools, see Managing Tools in the Toolbox.