Default Policy does not update all mailboxes according to the policy

If you use %g.%s@yourdomain.com as e-mail address policy criteria and you find out that not all your Users get updated with the policy but instead Alias is used, you need to check whether all user objects in Active Directory contain First Name and Last Name properties. The best way to check this in Exchange 2007 Exchange Management Console is to edit User properties under

• Recipient Configuration --> Mailbox -->
• select mailbox and click Properties
• Check User Information...