In Microsoft Exchange 2000, 2003 and 2007 Server operating systems, accounts with Enterprise Administrators mailbox access rights are denied by default. This restriction is also applicable if your login account is the Administrator account or you are a member of the Domain Admin or Enterprise Admin groups. In these cases also, access to all mailboxes other than your own will be denied, even if you have full administrative rights.

However, in Exchange 2000/2003/2007, administrative tasks can be performed without granting an administrator the rights to read anybody's mail.

To grant rights to a specific mailbox,

For Exchange 2007 Mailbox:

Method 1

1. Open the Exchange Management Console. Choose the Mailbox for which you want to grant permission. Right-click and select the Manage Full Access Permission menu option.
   
   
   
   
2. On the Manage Full Access Permission screen, grant full access to the Domain Admins user and click Manage. 
   
   
   
   
3. Click Finish to complete the operation.
   
   
   

Method 2
Open the Exchange 2007 management shell and enter the following syntax:

Add-MailboxPermission - identity <mailbox name> - accessRights fullAccess - User "<Domain name>\Domain Admins"

Example: To grant full access to the Mailbox 'Adams'.
Add-MailboxPermission - identity Adams - accessRights fullAccess - User "MyWorld\Domain Admins"

Note: To perform Exchange 2007 Brick-Level Backup, install the standalone version of MAPI from the Microsoft site.