We recently migrated one of our customers to Exchange Server 2010 from Exchange Server 2003 SP2 and our customer is reporting slow response from Outlook when mailboxes are being accessed; the clients are all Outlook 2003 SP2 running in cached mode, the server is a multi-role Exchange 2010 box running Mailbox, Hub Transport and CAS roles.
I know the obvious suggestion would be to upgrade the clients to Outlook 2010 but our customer is not in a position to do so just yet so we have to find a solution to this issue if we can.
The detail in the server logs suggests the issue is something to do with the RPC Client access Service. I've provided an extract below:
RpcDispatch: Client is being backed off -> Backend reported that it is too busy -> The process failed to get the correct properties. -> MapiExceptionRpcServerTooBusy: Unable to get properties on object. (hr=0x80004005, ec=2419)
Any help would be greatly appreciated.