on my all EXchange 2010 CAS Server , the  service  Micosoft Exchange service host can not start, when I  disable outlook any where, that is ok can restart. I had disable outlook any where then reinstall the rpc over http, enable outlook any wher ,proble same. how to solve it . thanks!

the error event id is 4999

M.Exchange.ServiceHostunknownM.E.D.D.S.E.<GetServersWithRpcClientAccessEnabled>d__4.MoveNextSystem.ArgumentException4543 unknown

ErrorReportingEnabled: False

I have never seen this.  I would guess that you have misconfigured Outlook Anywhere.

on sp1 & RU3 is no problem, but upgrade to sp3 &RU2 Happen this problem, and I have new install a cas server with sp3 and enable outlook anywhere, same error. then I had set HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\MSExchangeServiceHost\RpcHttpConfigurator\PeriodicPollingMinutes to 0 ,the service can start, but outlook any where not work. I guess the outlook anywhere config get from AD scheme, how to modify that?