Exchange 2010: Outlook 2003 cannot Connect !

Exchange2010

While configuring Outlook 2003 to connect with Mailbox on Exchange Server 2010 , you are most probably bound to face one of these errors:

  • Unable to open your default e-mail folders. You must connect to your Microsoft Exchange Server computer with the current profile before you can synchronize your folders with your offline folder file.
  • The action could not be completed. The connection to the Microsoft Exchange Server is unavailable. Outlook must be online or connected to complete this action.
  • Cannot start Microsoft Office Outlook. Unable to open the Outlook window. The set of folders could not be opened
  • Outlook could not log on. Check to make sure you are connected to the network and are using the proper server and mailbox name. The connection to the Microsoft Exchange Server is unavailable. Outlook must be online or connected to complete this action.

So what causes this weird behavior with Outlook 2003, when there are no such issues faced with Outlook 2007. This is due to the fact that by default Exchange 2010 configuration requires RPC encryption, where as Outlook 2003 does not use RPC encryption by default.

To tackle this Configure Outlook 2003 to use RPC Encryption:

  • Control Panel | Mail | Show Profiles |
  • Select profile | click Properties | Click E-mail Accounts | click Change existing e-mail accounts | click Next |
  • Select Account | click Change | click More Settings.
  • In dialog box | click Security tab | Select the Encrypt data between Microsoft Office Outlook and Microsoft Exchange Server check box | click OK

You can also Disable RPC Encryption in Exchange 2010 (not recommended) to tackle this error by using the cmdlet in Exchange Management Shell (EMS)

Set-RpcClientAccess “Server <Exchange_CAS_Server_Name> –EncryptionRequired $False

This should take care of the errors 🙂

Updated 03 May 2010: For further details refer http://support.microsoft.com/kb/2006508