This article was previously published under Q321419
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If you use a custom MAPI transport program with Microsoft Outlook 2002 (for example, if you use a program that permits you to select the security-level [classification] of an outgoing e-mail message), your custom MAPI transport program may not function as expected.
This problem may occurif your custom MAPI program uses preprocessor functions in a custom MAPI transport provider. This problem may occur even if the IMAPISupport::RegisterPreprocessor method returns the value S_OK becuase Outlook 2002 still may not call the preprocessor function of the custom MAPI transport provider.
To resolve this problem, install Microsoft Office XP Service Pack 3 (SP3).
For additional information about how to obtain and install Office XP Service Pack 3, click the following article number to view the article in the Microsoft Knowledge Base:
832671 Description of Microsoft Office XP Service Pack 3
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section of this article.
xcln outlook2002 transport provider preprocessor imapisupport