RPC Client Access is the main conduit for Outlook clients communicating to Exchange 2010. So when something happens to it, the impact can be classified as "not good"…..
While Exchange 2010 SP3 RU2 addresses issues with RPC Client Access that may be caused by RPC Client Access threads hanging on a mailbox server that is experiencing issues, there is an additional update that was recently released to resolve an issue with the RPC Client Access Service crashing when running on Windows 2008 R2 SP1.
This update is released as hotfix 2836445 and updates one file:
|File name||File version||File size||Date||Time||Platform|
File this one away just in case you run into it in the future!