We have a 4 CAS servers 2010 behind a Load Balancer. I am notincing the that some users trigger the below entry in the RPC CAS logs. These users are only opening one outlook session and they are not accessing any proxy mailboxes. The outlook client we are using is 2010. They ae all using the default throtling policy the only other custom throtling policy we have is for the blackberry service accuount which allows more connections. Any idea whay we are seeing this? 2012-04-05T12:48:32.666Z,185442,41818,/o=Skadden/ou=First Administrative Group/cn=Recipients/cn=Username,,OUTLOOK.EXE,14.0.6117.5000,Classic,,,ncacn_ip_tcp,,,1246 (rop::1246),00:00:00,,"RopHandler: OpenMessage: [TooManyObjectsOpenedException] The process failed to get the correct properties. -> [MapiExceptionSessionLimit] MapiExceptionSessionLimit: Unable to get properties on object. (hr=0x80040112, ec=1246) "

Take a look at their outlook profiles and see if they have any outlook plug in, some plug ins such as archiving\performance\search can open and hold on to the messages and not release them fast enough.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

We have several plug ins, some third party some developped inhouse. Can can we track which plug in is opening which session?

Hmmm not sure, maybe try enabling outlook logging. If that doesn't show there is probably no way of knowing which particular plug in is causing it. You may just have to resort to doing process of elimination and disable one at a time.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Thanks.