Topic Last Modified: 2010-08-16

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

MSExchangeTransport Queues

Counter Name

Categorizer Job Availability

Instance Name


Sample Interval


Server Role

Ex14. Common

Rule Path

Microsoft Exchange Server/Exchange 2010/Common Components/Hub Transport and Edge Transport/Transport

Rule Name

Transport categorizer jobs are partially unavailable - percentage of available categorizer jobs - Yellow(<99).


This alert indicates that a performance issue may occur on the affected Hub Transport server or Edge Transport server. This alert represents an hourly check that is performed to determine the Categorizer jobs that are available for message processing on the server.

The Categorizer component runs as a thread in the EdgeTransport.exe Worker Process in Microsoft Exchange Server 2010. Every message in Microsoft Exchange must pass through the Categorizer. The Categorizer is responsible for processing items from the submission queue. This processing includes the following operations:

  • Agent processing

  • Recipient resolution

  • Routing

  • Content conversion

  • Agent processing for external messages

  • Message packaging

    Although the Categorizer performs many operations, its primary operations are to resolve recipients and to route messages.

After the Categorizer processes the messages, it sends the messages to the delivery queues for local delivery or for remote delivery.

The transport server has a maximum number of jobs that may be used concurrently for message processing. When the available jobs are consumed, the Categorizer cannot process additional messages.

In this scenario, you may experience the following symptoms:

  • The mail submission queue may build up on the transport server.

  • Delivery queues do not build up.

When the number of available Categorizer jobs is fewer than 100 percent, it indicates that one or more Categorizer jobs are stuck. In this scenario, a component may be preventing the particular job or jobs from finishing in a timely manner.

As a general guideline, if the number of available Categorizer jobs is fewer than 99 percent, a problem may affect the Transport service. A severe problem may exist if the number of available Categorizer jobs is fewer than 90 percent.

This alert may indicate that a bottleneck affects the Transport server, or that a problem affects the Transport service.

User Action

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

  • Review the Application log and System log on your Exchange 2010 servers for related events. For example, events that occur immediately before and after this event may provide more information about the root cause of this error.

  • Review the Operations Console in Operations Manager for detailed information about the cause of this problem. For more information, see the "Introduction" section in this article.

  • Check the MSExchangeTransport Categorizer performance counter by using Windows Reliability and Performance Monitor.

  • Check the MSExchangeTransport Queues\Messages Completing Categorization performance counter to determine the percentage of messages that complete categorization over the last five minutes. A value that is consistently less than 100 indicates that the categorizer performance is insufficient to handle the rate of message submissions. This may help you determine the effect that a stuck job has on categorizer throughput.

  • Use the Get-Message cmdlet together with the IncludeComponentLatency parameter to determine whether any messages are stuck in the Categorizer. The following command returns a list of messages in the Categorizer:

    Copy Code
    $ActiveMsgs = get-message -server $server -filter {queue -eq "submission" -and Status -eq 'active'} -IncludeComponentLatencyInfo
    Each list entry contains a MessageLatency property that indicates the time that has passed since the message was received by the local server. The ComponentLatency property lists the components that have added more than one second of latency to the message processing. The last component listed may indicate where a message is stuck. If the affected component is a third-party agent, you may have to contact the component vendor to obtain additional troubleshooting information.

  • Restart the MSExchangeTransport service to release any messages that are stuck in the Categorizer. This action may be useful when a transient error in a component prevents the categorizer job from finishing.

  • Use the Exchange Troubleshooting Assistant (ExTRA) to obtain Event Tracing for the Transport component.

    For more information, see the Scotch's Blog article, Another Method of Obtaining ExTRA Traces. To obtain the Exchange Troubleshooting Assistant, visit the Microsoft Exchange Troubleshooti n g Assistant v1.1 Web site.

    The content of each blog and its URL are subject to change without notice. The content within each blog is provided "AS IS" with no warranties, and confers no rights. Use of included script samples or code is subject to the terms specified in the Microsoft Terms of Use.

  • Resolve your issue by using self-support options, assisted support options, and other resources. You can access these resources from the Exchange Server Solutions Center. From this page, click Self-Support Options in the navigation pane to use self-help options. Self-help options include searching the Microsoft Knowledge Base, posting a question at the Exchange Server forums, and others. Alternatively, in the navigation pane, you can click Assisted Support Options to contact a Microsoft support professional. Because your organization may have a specific procedure for directly contacting Microsoft Technical Support, be sure to review your organization's guidelines first.

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.