When to use Recovery Storage Group
recover individual user mailbox and use exMerge tool to merge the backup data with the existing mailbox.
To use the feature, you must have a working mailbox store. You mount the mailbox store from backup in the same computer or on another exchange server that is in the same administrative group.
If your mailbox store cannot be mounted because of data corruption, you cannot use the Recovery Storage Group feature. You should restore the mailbox store from backup and mount it.
When you create the Recovery Storage Group, if you cannot mount the mailbox store you add it to the Recovery Storage Group, it is possible that the directories of Recovery Storage Group database file and log files are not empty.
