Topic Last Modified: 2010-01-26

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 Availability

Alert Type


Rule Path

Microsoft Exchange Server/Exchange 2010/Client Access/Information Worker

Rule Name

A request to access a public folder failed.


This Error event indicates that the Microsoft Exchange Availability service could not successfully retrieve Schedule+ Free Busy data for one or more legacy Exchange mailboxes. A legacy Exchange mailbox refers to a mailbox that resides on an Exchange 2000 or Exchange 2003 server. The Exchange Availability service is responsible for retrieving Schedule+ Free Busy data for a set of mailboxes. If the mailbox resides on a computer that is running Exchange 2007 or Exchange 2010, the Availability service retrieves the data from the mailbox itself. However, if the mailbox resides on an Exchange 2000 or Exchange 2003 server, the Availability service retrieves the data from Public Folders. This event occurs when the Exchange Availability service does not retrieve the data from Public Folders.

This event can be logged because of various reasons. Increase the diagnostic logging level of MSExchange Availability service to find the root cause of this error.

User Action

To resolve this error, follow these steps:

  • Increase the diagnostic logging level of MSExchange Availability service. To do this, follow the steps shown here:

    Incorrectly editing the registry can cause serious problems that may require you to reinstall your operating system. Problems resulting from editing the registry incorrectly may not be able to be resolved. Before editing the registry, back up any valuable data.
    1. Start Registry Editor (regedit).

    2. Locate the following registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchange Availability\Diagnostics

    3. In the results pane, change the Value data of all keys (except Default) to 5.

    4. Exit Registry Editor.

  • Review other related Error and Warning events in the Application log. These related events may help you find the root cause of this error.

For detailed information about how to configure logging, see Change Logging Levels for Exchange Processes.

If you cannot resolve this error using the options suggested here, contact Microsoft Product Support Services. For more information, visit the Microsoft Help and Support Web site.

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.