I need to restore Active Directory to a different hardware platform. Which backup method should I use to avoid problems?

Active Directory restoration can be tricky because there are several rules that must be observed.

Even though domain controllers are supposed to provide redundancy to each other, there are platform-specific differences that prevent data from one server from being used to restore another. You can always use a system state or critical volumes backup to restore a domain controller on which the backup was created. If you create Backup A on Server A, you can use Backup A to restore Server A at any time.

However, you cannot use a system state or critical volumes backup to restore a different domain controller or restore that domain controller to different hardware. You can't use Backup A to restore the Active Directory environment that existed on Server B;  you can't "fix" a problem on Server B with Server A's backup. Similarly, you can't restore Backup A to Server B and expect it to work as Server A.

If you must restore an Active Directory backup to a different hardware platform, use a full server backup. For example, if Backup A is a full server backup -- not a system state or critical volumes backup -- you can restore Server A on another server -- effectively making that new hardware Server A.

Courtesy: Stephen J. Bigelow