An Active Directory server can be recovered from a bare metal backup, but be aware that this is an older image of the domain controller. There are specific steps that must be completed before starting the recovered server in normal mode. If the server is booted into normal mode before completing these steps, replication will proceed with inappropriate tracking numbers, resulting in an inconsistent database among domain controller replicas.
After a bare metal image is restored, when the server is booted for the first time, and it is a member of an Active Directory forest, it must be started in Directory Services Restore Mode (DSRM). You then must complete a restore of the last master and incremental file backups of the server.
If a file backup of the server is not available, the server must be started in Directory Services Restore Mode and the database restored from backup registry value must be set to 1. For instructions on how to edit this registry value, please review the Microsoft TechNet article, Backup and Restore Considerations for Virtualized Domain Controllers.
Note: To eliminate the possibility of starting in normal mode, when booting an Active Directory server the first time after a bare metal recovery, do so with the server disconnected from the network. After confirming the server is running in DSRM, the network can be reconnected to proceed with the file backup.
Once the file backups have been restored or the “database restored from backup” registry value has been set to 1, restart the domain controller in normal mode.