Event Type:ErrorEvent Source:MSExchangeISEvent Category:General Event ID:9646Date:10/10/2008Time:8:31:44 AMUser:N/AComputer:EXCHANGEDescription:Mapi session "/o=THA/ou=First Administrative Group/cn=Recipients/cn=janderson" exceeded the maximum of 32 objects of type "session". For more information, click http://www.microsoft.com/contentredirect.asp. Can anyone shed some light on this error and how to fix it. Thanks. Phill

Hi Phill, First thing check this article, it is listed as a one of the symptom.. Windows 2003 Scalable Networking pack and its possible effects on Exchange http://msexchangeteam.com/archive/2007/07/18/446400.aspx Looks like server is affected from Scalable Networking Pack (SNP) feature and TCP/IP Offload-enabled on network adapter so first thing I would suggest you to Check RSS and TCP chimney Offload settings which are by default enabled in Windows 2003 SP2. Reference: You may experience network-related problems after you install Windows Server 2003 SP2 or the Scalable Networking Pack on a Windows Server 2003-based computer http://support.microsoft.com/kb/936594 Additionally, run ExBPA to find out any non-standard settings or errors on your Exchange server. http://exbpa.com/

Check below KB too if you are using Exchange 2003 Event ID 9646 is logged in the application event log of your Exchange Server 2003 computer when a client opens many MAPI sessions http://support.microsoft.com/kb/842022

Thanks for your quick reply, however this error message applies only to one mailbox, I have several same type network cards, (laptops) within our domain and they are not expericing any issue, the user in question does not apper to be affected this is just an error showing up in the logs on the Exchange server itself. I have run Exchange best practice and it does not show any critical errors.

Actually we need to check TCP/IP Offload settings on the Exchange Server, refer the article. If it logs error for only one user then you can check how user is using outlook as per KB842022 and any error at client level. You may also increase MAPI sessions per user by changing registry as per same KBto stop getting error if you feel that evicted user really requires multiple MAPI sessions.

Hi, Philldmcc, I assume your question has been answered, and I'd like to change the status to "Marked as answer", please feel free to post here if you have any update