Moving SYSVOL Files
The SYSVOL is identical on all Domain Controllers
The System Volume (SYSVOL) contains a shared copy of the domain's public files. It includes a copy of the domain's Group Policy settings and the domain's user logon scripts. The files in SYSVOL should be identical on every domain controller in the domain. The files in SYSVOL are usually stored at C:\Windows\SYSVOL.
The File Replication Service (FRS) replicates the contents of SYSVOL to all of the domain controllers in the domain. Its purpose is to to ensure that the files in SYSVOL are always identical.
Windows Server 2008 replaced FRS with the Distributed File System Replication Service (DFSR). DFSR can be used exclusively when migration from FRS is completed.
How to Respond
A question arises when there is more than one domain controller for the same domain. In this case you need to tell U-Move how to handle discrepancies between the loaded SYSVOL and the copies of SYSVOL on the other domain controllers.
Unless otherwise instructed you should generally select Authoritative Restore.
If you are restoring two or more domain controllers in the same domain, select Non-authoritative Restore on the second, third, fourth, etc, domain controllers in the domain. The domain controllers will erase their local copy of SYSVOL and then replicate SYSVOL from the domain's authoritative domain controller.
If your SYSVOLs are out of sync and you need to cross-replicate SYSVOL back-and-forth between two or more DCs, select Normal Restore. (This is rarely needed. It can cause harmful side effects; see caution below.)
Consequences of incorrect response
If you select Non-authoritative for all domain controllers but fail to select Authoritative for at least one, the SYSVOL replication service (DFSR or FRS) will stall. This is because the service will wait indefinitely for an authoritative replication that it will never receive.
Normal Restore is Abnormal
Caution: Normal Restore is peculiar and should not be used unless you understand how it works. If you select a Normal Restore, FRS will hide all the SYSVOL files in the subfolder “NtFrs_PreExisting___See_EventLog”. FRS will move the files back to their original locations only when it can successfully cross-replicate with another domain controller and compare timestamps. (It will compare timestamps and select whichever file is newer between the two domain controllers.) But until at least one such successful replication occurs, all the files in SYSVOL will remain hidden in the PreExisting folder. This means that until at least one successful replication occurs the SYSVOL will be empty and Group Policy will fail with mysterious error messages. For example, “Windows cannot obtain the domain controller name for your computer network. (The specified domain either does not exist or could not be contacted.) Group Policy processing aborted.” (Event ID 1054).
You should always select Authoritative Restore (not Normal Restore) when moving only one DC. If you accidentally selected Normal Restore you can fix the problem by running U-Move again and this time selecting Authoritative Restore.
Read-only Domain Controller (RODC)
If you are restoring a read-only domain controller (RODC) you should generally select Non-authoritative Restore for the RODC. Exception: If you are testing a single RODC in an isolated network in your lab such that it has no access any other domain controllers, you should choose Authoritative Restore to allow the SYSVOL replication service to start on the RODC.
For more information about SYSVOL recovery
For information on how to recover SYSVOL manually, see the following Microsoft technical articles. These are for reference only. U-Move will automatically recover SYSVOL by doing all the steps described in the technical articles. For example, U-Move will automatically synchronize the Group Policy version numbers in SYSVOL with the Group Policy Containers (GPCs) in Active Directory.
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