Topic Last Modified: 2006-01-09

The Microsoft® Exchange Server Analyzer Tool reads the following registry value to determine whether a Virus Scanning Application Programming Interface (VSAPI) library file is registered with the Microsoft Exchange Information Store service:


Antigen 8.0 for Microsoft Exchange is a Sybari product. When Antigen 8.0 for Microsoft Exchange is installed on Exchange 2000 Server or Exchange Server 2003, the Library registry entry will have a value of ANTIGENVSAPIEx.DLL. This library file performs several VSAPI-related functions in Antigen 8.0 for Microsoft Exchange.

The Exchange Server Analyzer also queries the CIM_Datafile Microsoft Windows® Management Instrumentation (WMI) class to determine the value of the Version key for ANTIGENVSAPI.DLL. If the value for the Version key indicates that the build number is less than 1517 for this file, a warning is displayed.

A version number of less than 1517 for ANTIGENVSAPI.DLL indicates that the latest version of Antigen 8.0 for Microsoft Exchange is not installed. A software update is available for Antigen 8.0 for Microsoft Exchange from the Sybari Web site. This update is highly recommended and can improve overall performance and reliability.

To correct this warning
  1. Visit the Sybari Web site, "Licensed Download Center" (

    Web addresses can change, so you might be unable to connect to the Web site mentioned here.
  2. Download the latest update for your version of Antigen 8.0 for Microsoft Exchange.

  3. Make a full backup of the Exchange Server computer.

  4. Install the latest update to Antigen 8.0 for Microsoft Exchange.

For more information about how to use antivirus software with Exchange Server, see the following Microsoft Knowledge Base articles:

For a list of third-party antivirus software available for Exchange Server, see the Exchange Server Partners: Antivirus Web site (