Article ID: 2529715 - Last Review: August 24, 2011 - Revision: 2.0

Slow network or replication issues after you change the number of virus scanning API threads in Microsoft Exchange Server 2010

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SYMPTOMS

Consider the following scenario:
  • You run the Exchange Server Analyzer tool on a server that has Microsoft Exchange Server 2010 installed.
  • The Exchange Server analyzer tool reports the following warning message:
    Warning Virus scanning API (VSAPI) low thread count Server server name. The number of virus scanning API threads on server server name is too low and may cause performance degradation. Current number of threads: number. Based on the current hardware configuration, a value of number is recommended.
  • You change the number of virus scanning API threads to the recommended number from the Exchange Server Analyzer tool on the computer.
In this scenario, the network performs slowly on the Exchange server, or replication issues occur on the Exchange server.
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CAUSE

This issue occurs because the Exchange Server Analyzer tool uses an incorrect method to calculate the recommended number of virus scanning API threads. Therefore, the tool suggests a much larger number than the number that is suggested by the antivirus scanner company.

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RESOLUTION

To resolve this issue, install the following update rollup:
2582113  (http://support.microsoft.com/kb/2582113/ ) Description of Update Rollup 5 for Exchange Server 2010 Service Pack 1
Note This hotfix removes the incorrect ScanningThreads rule from the Exchange Server Analyzer tool.
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STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
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MORE INFORMATION

For more information about the Exchange Virus Scanning API, visit the following Microsoft TechNet website:
General information about the Exchange Virus Scanning API (http://technet.microsoft.com/library/aa997059(EXCHG.80).aspx)

For more information about the Exchange Server Analyzer tool, visit the following Microsoft TechNet website:
General information about the Exchange Server Analyzer tool (http://technet.microsoft.com/exchange/bb288481.aspx)
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APPLIES TO
  • Microsoft Exchange Server 2010 Enterprise
  • Microsoft Exchange Server 2010 Standard
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Keywords: 
kbfix kbexpertiseinter kbexpertiseadvanced kbsurveynew KB2529715
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