Topic Last Modified: 2006-09-06

The Microsoft® Exchange Server Analyzer Tool includes a performance data collection engine that is used to query performance counter objects on computers that are running Exchange 2000 Server or Exchange Server 2003. The performance data collection engine collects data from the Cat: Categorizations in progress performance counter of the SMTP Server performance object to analyze performance data.

The Cat: Categorizations in progress performance counter shows the number of categorizations in progress.

For this query, the Exchange Server Analyzer retrieves a sample every 6 seconds for a two-minute period. The Exchange Server Analyzer reports the average value for the performance counter during the collection interval.

If the Exchange Server Analyzer determines that the minimum number of categorizations in progress over the sample period is never equal to zero, the Exchange Server Analyzer displays a warning.

The categorizer performs the following core operations:

If the server is not under heavy load, this warning may indicate that the Inetinfo.exe process, or resources that the Inetinfo.exe process depends on, are deadlocked.

The Simple Mail Transfer Protocol (SMTP) service runs in the Inetinfo.exe process and when messages pass through the transport subsystem, SMTP makes heavy use of Internet Information Services (IIS) resources.

A deadlock occurs when two or more processes (or threads) each wait for the other to complete before the process can continue. The result is that all the processes (or threads) stop responding (hang). In a deadlock, processes never finish executing and system resources are occupied. This prevents other jobs from starting.

To address this warning:

For More Information

For more information about Inetinfo.exe, see "Internet Information Services" in the Technical Reference Guide for Exchange Server 2003 (

For more information about how to troubleshoot a deadlocked process, see Microsoft Knowledgebase article 919791 "How to use the Debug Diagnostics Tool to troubleshoot high CPU usage by a process in IIS" (

For more information about Exchange Server performance, see the "Performance and Scalability Guide for Exchange Server 2003" (

For more information about how to troubleshoot Exchange Server performance issues, see "Troubleshooting Microsoft Exchange Server Performance" (