Exchange 2007 client connectivity error "MAPI session exceeded the maximum of 32 objects of type session"

check this for exchange 2007:

http://support.microsoft.com/kb/925815

Seeing a lot of these recently.
Are the users who have the problem local or remote? How are they connecting? VPN, Outlook Anywhere, something else?

The MAPI sessions aren't ending correctly, it is a matter of finding out why that is.

Simon.

The clients facing the problem  are connecting using Outlook 2003. Also the same clients can connect using OWA without any problems. If i increase the no. of sessions in the registry as per the knowledge base 925825 as suggested by amheswariit will solve the problem temporarily but I want to know why the sessions keeps increasing and how to stop it. Increasing the session limit value in registry will have a negative impact on the performance of the Exchange server.

Thanks

Arshad

The fact that they can use OWA correctly is not really an issue here as the entire connection is made by the Exchange server.

The issue is that for some reason the connections these clients are making to the server are not being dropped correctly.
You answered the question on version, but not on how they connect.

If they are all LAN clients then you have to start looking at third party products that are possibly interfering with the connections.
If they are all remote clients then firewalls, VPN software etc could be the issue. It may not be a technical issue, but a problem with the way that the clients disconnect or are using Outlook. It could be a combination of the products you are using and the way that the users work.

Simon.

Arshad, We had the exact same issue as you do,  with a similar setup as what you have... the users that had the issue are all wireless clients running XP OS with Outlook 2003.  when the users try open their outlook it would just say server not available  or down for maintenance... then after that error we took a look in the server event viewer and had the same error logged. "MAPI session exceeded the maximum of 32 objects of type session"

What we did to solve the issue was the following..  and after doing the below no more probs..  still have no clue why this happened or what causes it...  hope the below helps you..

Fix the issue with Exchange Command Shell using this command:

add-adpermission -Identity "User Name" -user USERID -AccessRights extendedright -ExtendedRights "View Information Store status"

Fill in each persons username, and Identity name.

****The MSExchangeIS information store has to be restarted to apply these AD Permission Changes.****

We had that exact same problem with Exchange 2007 and Windows 2003 SP2.  The problem showed up with remote users using VPN.  Disabling the TCP offloading fixed my problem.  
Check in the Windows registry at:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Change the EnableTCPChimney value to "0".
This requires a reboot.

Or you can do it from a command line without a reboot.
"Netsh int ip set chimney DISABLED"

JacquesDreyer - Your fix would simply allow the max MAPI sessions to be unlimited.  arshadr - Is this what you are looking for?

I see a lot of stuff pointing to what libertytax said.
http://support.microsoft.com/kb/944011

We are having the same issue randomly and using TCPView to find the users computer and killing the sessions seems to be the temporary work around.

We had the very same issue.

You can find some help here:
http://www.azaleos.com/blog/index.php?q=node/41

Hope it helps.