So now you have a production Information Store (IS) mounted on a recovery server. What do you need to do to retrieve the information contained in a mailbox? Because an Exchange Server mailbox is just another attribute of an Active Directory (AD) object—and because you've restored to a system that's running an independent AD forest—an association no longer exists between the mailbox and the original account. You essentially have an orphaned mailbox that doesn't belong to anyone and grants no account access. No one can read its contents.
To make the mailbox accessible, you first need to inform the system that the mailbox is orphaned. To do so, use Exchange System Manager (ESM) to expand the containers below the IS that you just restored. Right-click the Mailboxes container, then choose Run Cleanup Agent from the resulting menu. The agent flags all the mailboxes in this IS copy as disconnected. As Figure A shows, a red X appears over the mailbox icon.
Use the Microsoft Management Console (MMC) Active Directory Users and Computers snap-in to create a user account for the mailbox that you need to access. When you get to the wizard's third screen, clear the Create an Exchange Mailbox check box. Now, return to ESM, right-click the mailbox that you need to access, and select Reconnect from the resulting menu. In the wizard, select the new user account. When you use this user account to log on, Outlook will let you access the mailbox contents and save them to a personal store (.pst) file. If you need to recover multiple mailboxes—or even the entire IS—you can use the Microsoft Exchange 2000 Server Resource Kit's Mailbox Connect (Mbconn) tool. Mbconn lets you create and reconnect AD accounts for multiple orphaned mailboxes simultaneously. After you associate the mailboxes with an AD account, you can use the resource kit's Exmerge tool to extract their contents to .pst files.