Hi All! I have now created new registry entries in Outlook client computer under HKCU. They are: [HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\RPC] "EnableRPCtunnelingUI"=dword:00000001 "DisableRpcTcpFallback"=dword:00000001 "RpcTraceEnable"=dword:00000001 "ConnectTimeout"=dword:000493e0 "ConnectTimeoutLow"=dword:000493e0 "RFRTimeout"=dword:000493e0 This time the outlook tries to connect to Exchange not over 135 port (I used outlook /rpcdiag). When I entried my user information and password on the logon popup window, I became the error message that says: "No connection to Exchange Server, Outlook must be either in online mode or connected." If I click "Cancel", I became the error: "Your standard mail folder cannot be opened. The file C:\Documents and Settings\mcicek\Local Settings\Application Data\Microsoft\Outlook\outlook0.ost is not a offline folder file" Then I cannot connect to Exchange. That is the situation now. I think there must be other Registry-Entries which are modified or created on the client computer??! Best Regards Mustafa