Hi, I installed OCS 2007 R2 on Windows 2008 R2 (I know this is not yet supported by MS) and everything is working. With Communicator 2007 R2 clients I can see presence information and can send instant messages. I’ve configured Exchange 2010 OWA & OCS integration. Both the E2K10 CAS and OCS Servers are fully up-to-date with MS Update. From OWA 2010 I can see presence information and the Contacts list shows OCS contacts. When a user changes presence from within OWA this change is visible to other users. Problems: · Send IM from OWA to another user with OWA and Communicator 2007 R2 client signed in: IM arrives under Communicator 2007 client. A ‘reply’ results in: the following message was not delivered to <user> ID:504 · Cannot send IM from OWA to another user with OWA signed in and Communicator 2007 R2 client NOT signed in. After clicking on Send I get: This message couldn’t be delivered to all recipients because some recipients are offline or don’t want to be disturbed. Anyone any ideas? Martijn

I've removed OCS and installed OCS 2007 R2 on a new W2k8 SP2 Server. OWA 2010 IM is working fine now.Thanks!Martijn