This is a very usual problem that helpdesk people face, that has a very simple solution.

In Outlook 2010 we can finally add multiple Exchange accounts, and use all the features they offer ( in previous versions Outlook Mail Profile could handle multiple classic email accounts (POP3, etc) but only oneExchange account.

1. Close Outlook 2010 ( else you will get this error ):

2. Go to Start / Control Panel, here select Small Icons ( from the right-up corner menu ), and then click on Mail:

3. A new window will appear. Here click on E-mail Accounts:

4. In the new window, select the E-mail tab, then click on New:

5. In the new window select E-mail Account, then click Next:

6. At the next step, select Manually configure server settings or additional server types, and click Next:

7. At the next step you have to provide the settings for your Exchange Server, and the account that you want to configure, and then click Next, and after that Finish.

8. After you made all this steps you have the second Exchange Account configured in Outlook:

Enjoy !

If you encounter any problems feel free to comment / contact me