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

Internal cache error. Hash table value is incorrect. Restart Active Directory Topology service or restart server. Check System log for hardware errors.


This Error event indicates that a hash table iterator is invalid. A hash table stores frequently accessed and fast-changing information in the memory cache. The records are added and deleted dynamically to maintain optimal memory use. An iterator is used to move through the records of a hash table. If the iterator is invalid, it cannot use a hash table.

This event may be caused by internal memory issues.

User Action

To resolve this error, do one or more of the following:

  • Restart the Active Directory topology service. If the error persists, restart the Exchange server that logged this event.

  • Review the System log for hardware issues.

  • Verify that the version of DSAccess.dll matches the version of its companion DLLs. For more information, see Exchange Server 2003 Active Directory Integration.

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.