Topic Last Modified: 2010-05-03

The Microsoft Exchange Server 2010 Management Pack for System Center Operations Manager includes a performance data collection engine that is used to query performance counter objects on computers running Exchange 2010. For this Operations Manager rule, data is collected by using the performance counter specified in the Details table.

To review the value of the performance counter that generated this alert, in Operations Manager, double-click this alert, and then click the General tab. Review the description of the alert that includes the variables specific to your environment.


Product Name


Product Version

14.0 (Exchange 2010)

Object Name


Counter Name

Download Task Queued

Instance Name


Sample Interval


Server Role

Ex14. Client Access

Critical Error Threshold


Rule Path

Microsoft Exchange Server/Exchange 2010/Client Access/File Distribution Service

Rule Name

MSExchangeFDS:OAB: Download Task Queued - sustained for 10 hours - Red (>1).


The Download Task Queued performance counter shows 1 if an offline address book (OAB) download task is queued for execution and shows 0 if it is not.

After installing an Exchange 2010 Client Access server, the Microsoft Exchange File Distribution Service gets installed and is started. The Microsoft Exchange File Distribution Service is responsible for downloading OAB content from the Exchange server that is configured to be the OAB generation server. Each attempt to download an OAB by a Client Access server is considered a download task.

This alert indicates that 10 or more OAB download tasks have been queued for at least 10 hours. This means that the Client Access server is unable to complete OAB data download tasks in a timely manner. This alert may be caused by network problems between the Client Access server and the OAB generation server, or the OAB generation server may be unavailable or experiencing performance issues.

User Action

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

  • Verify network connectivity between the Client Access server and the OAB generation server.

  • Verify that the OAB generation server is available.

  • Verify that the OAB generation server is not experiencing severe performance problems. You can investigate CPU usage, as well as disk and memory bottlenecks, on your servers.

If you are having difficulty resolving the issue, contact Microsoft Product Support. For information about contacting support, visit the Contact Us page of 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.