“Setup encountered a problem while validating the state of Active Directory: Couldn’t find the Enterprise Organization Container” while installing Exchange Server 2013

As Exchange 2013 reached general availability and as I was working on building my Exchange 2013 lab I got into the following issue while preparing the Active Directory :

Here is what I found at ExchangeSetup.log :

The solution was to go to Active Directory Users and Computers , click View tab , choose Advanced Features then delete Microsoft Exchange System Objects container 

Once done , Active Directory preparation was successfully completed