Hi, We seem to be suffering a spate of users being disconnected from Outlook. We are running Exchange 2003 and the clients experiencing the problems are Outlook 2003 and 2007. All are on the same LAN. In the Exchange server I get the following error message: Event ID: 9646 Mapi session "/o=COMPANY NAME/ou=UK/cn=USERS/cn=JOHN.SMITH" exceeded the maximum of 32 objects of type "session". IP connectivity is fine (they can browse shares on the mail server) and eventually (after an hour or so), they can connect back on to the Exchnage server. I found this article http://support.microsoft.com/kb/842022 and made all the changes it recommended, increasing the limit from 32 to 64. I've also got people to clear out their mailboxes so they don't have more than 3000 items. but the disconnections still keep happening.... Does anyone have any ideas about what to do next? Thanks for your help, Adam

Hello, Giving the fact that you are getting the 9646 event for the ''session'' object that usually means that disconnected OL users leave behind orphaned sessions. This can come from a few diffrent causes each of those having their own fix. Here is a list of things to try/check: On the Exchange servers: 1. HP network cards teaming enabled. This is a known cause for this type of scenario. If you have teaming enabled on the network cards, break it and retest without it. 2. TCP Chimney. Disable it by running the following command and rebooting afterwards: Netsh int ip set chimney DISABLED (http://support.microsoft.com/default.aspx?scid=kb;EN-US;242468) 3. Add the following registry key on the servers: MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\KeepAliveTime , DWORD, value 300000 ( that means 5 minutes in miliseconds) Hope it helps, Mihai

Thanks Mihai, we weren't using teamed cards, but the TCP Chimney and KeepAliveTime seem to have fixed it. Many thanks for your help. Adam