About Exchange Information Store Restore Methods
There are three different Exchange Information Store restore methods. Determining which one to use comes down to picking the appropriate method for the goal of the restore. Restoring for the purposes of disaster recovery usually leads to restoring over the current information store while restoring to a temporary folder or to a recovery information store is better suited for retrieval purposes.
Download to a temporary local folder - This option downloads the Exchange files to a folder you choose. If you want to restore a full backup by this method, select the revision and restore the files. If you want to restore an incremental backup, you need to restore the files from the most recent full backup through to that incremental revision. For example, in the window from step (5), if you wanted to restore the information store to 3/21/2016, you would need to restore the files from the full backup on 3/19/2016 and the files from the incremental backups on 3/20/2016 and 3/21/2016; each revision has to be restored separately.
Restore over the current Information Store - When you select this method, you overwrite the information store currently on the Exchange server with the one you choose. This method replaces the current information store so be careful when restoring this way. You can pick either a full or an incremental backup to restore when using this method.
Restore to a Recovery Information Store - If you choose to restore to a recovery information store, this method allows you to restore to a "sandbox". The recovery information store can be present alongside the production information store which allows you to transfer data between the two for restores of entire mailboxes or bulk messages. For this option to work, you need to create a recovery information store before running the restore (otherwise this option is grayed-out). You can pick either a full or an incremental backup to restore when using this method.
Creating a Recovery Information Store
The process for creating a recovery information store is relatively simple with one caveat. When creating the recovery mailbox database, the (.edb) file must have the same name as the (.edb) file you intend to restore.
If the name of our Exchange database file was "mailstore1.edb" then the command to create the recovery mailbox database should be the following (from the example here):
New-MailboxDatabase -Recovery -Name RDB -Server MBX1 -EdbFilePath "C:\Recovery\RDB\MAILSTORE1.EDB" -LogFolderPath "C:\Recovery\RDB"
...where -Name sets the name of the recovery mailbox database (this can be anything) and -Server specifies the Exchange server you are adding the recovery mailbox database to. In this example the name given to the recovery database is "RDB" and the Exchange server's name is "MBX1."