How to Configure the Exchange Databases so That the Restore Process Overwrites Them
This topic explains how to configure Exchange databases so that they will be overwritten during a restore using Backup.
Before You Begin
Before you perform the procedure in this topic, be aware that you should not use this option unless you are certain that you must overwrite the database.
Procedure
To configure the Exchange databases so that the restore process overwrites them
Open Exchange System Manager. Click Start, point to Programs, point to Microsoft Exchange, and then click System Manager.
In Exchange System Manager, navigate to the database that you want to restore, right-click it, and then click Properties.
Mailbox store properties
On the Database tab, select the This database can be overwritten by a restore check box.
Enabling the database to be overwritten during a restore