Fix an Unsuccessful DC Demotion

The DCPROMO (Dcpromo.exe) utility is used for promoting a server to a domain controller and demoting a domain controller to a member server (or to a standalone server in a workgroup if the domain controller is the last in the domain). As part of the demotion process, the DCPROMO utility removes the configuration data for the domain controller from the Active Directory. This data takes the form of an "NTDS Settings" object, which exists as a child to the server object in the Active Directory Sites and Services Manager.

The information is in the following location in the Active Directory:CN=NTDS Settings,CN=<servername>, CN=Servers,CN=<sitename>,CN=Sites, CN=Configuration,DC=<domain>…

The attributes of the NTDS Settings object include data representing how the domain controller is identified in respect to its replication partners, the naming contexts that are maintained on the machine, whether or not the domain controller is a Global Catalog server, and the default query policy. The NTDS Settings object is also a container that may have child objects that represent the domain controller’s direct replication partners. This data is required for the domain controller to operate within the environment, but is retired upon demotion.In the event that the NTDS Settings object is not removed properly (for example, the NTDS Settings object is not properly removed from a demotion attempt), the administrator can use the Ntdsutil.exe utility to manually remove the NTDS Settings object. The following steps list the procedure for removing the NTDS Settings object in the Active Directory for a given domain controller. At each NTDSUTIL menu, the administrator can type help for more information about the available options.

Caution: The administrator should also check that replication has occurred since the demotion before manually removing the NTDS Settings object for any server. Using the NTDSUTIL utility improperly can result in partial or complete loss of Active Directory functionality.

Procedure

1. Click Start, point to Programs, point to Accessories, and then click Command Prompt. At the command prompt, type

ntdsutil

and then press ENTER.

2. Type

metadata cleanup

and then press ENTER. Based on the options given, the administrator can perform the removal, but additional configuration parameters need to be specified before the removal can occur.

3. Type

connections

and press ENTER. This menu is used to connect to the specific server on which the changes occur. If the currently logged on user does not have administrative permissions, alternate credentials can be supplied by specifying the credentials to use before making the connection.

To do so, type

set creds domain nameusernamepassword

and press ENTER. For a null password, type null for the password parameter.

4. Type

connect to server servername

and then press ENTER. You should receive confirmation that the connection is successfully established. If an error occurs, verify that the domain controller being used in the connection is available and the credentials you supplied have administrative permissions on the server.

Note: If you try to connect to the same server that you want to delete, when you try to delete the server that step 15 refers to, you may receive the following error message:

Error 2094. The DSA Object cannot be deleted0x2094

Note: Windows Server 2003 Service Pack 1 eliminates the need for steps 3 and 4.

5. Type

quit

and then press ENTER. The Metadata Cleanup menu appears.

6. Type

select operation target

and press ENTER.

7. Type

list domains

and press ENTER. A list of domains in the forest is displayed, each with an associated number.

8. Type

select domain number

and press ENTER, where number is the number associated with the domain to which the server you are removing is a member. The domain you select is used to determine if the server being removed is the last domain controller of that domain.

9. Type

list sites

and press ENTER. A list of sites, each with an associated number, is displayed.

10. Type

select site number

and press ENTER, where number is the number associated with the site to which the server you are removing is a member. You should receive a confirmation listing the site and domain you chose.

11. Type

list servers in site

and press ENTER. A list of servers in the site, each with an associated number, is displayed.

12. Type

select server number

where number is the number associated with the server you want to remove. You receive a confirmation listing the selected server, its Domain Name Server (DNS) host name, and the location of the server’s computer account you want to remove.

13. Type

quit

and press ENTER. The Metadata Cleanup menu appears.

14. Type

remove selected server

and press ENTER. You should receive confirmation that the removal completed successfully. If you receive the following error message:

Error 8419 (0x20E3) The DSA object could not be found

the NTDS Settings object may already be removed from the Active Directory as the result of another administrator removing the NTDS Settings object, or replication of the successful removal of the object after running the DCPROMO utility.

Note: You may also see this error when you attempt to bind to the domain controller that is going to be removed. Ntdsutil needs to bind to a domain controller other than the one that is going to be removed with metadata cleanup.

15. Type

quit

at each menu to quit the NTDSUTIL utility. You should receive confirmation that the connection disconnected successfully.

16. Remove the cname record in the _msdcs.root domain of forest zone in DNS. Assuming that DC is going to be reinstalled and re-promoted, a new NTDS settings object is created with a new globally unique identifier (GUID) and a matching cname record in DNS. You do not want the DC’s that exist to use the old cname record.

As best practice you should delete the hostname and other DNS records. If the lease time that remains on Dynamic Host Configuration Protocol (DHCP) address assigned to offline server is exceeded then another client can obtain the IP address of the problem DC.

Now that the NTDS setting object has been deleted we can now delete the following objects:

1. Use ADSIEdit to delete the computer account in the OU=Domain Controllers,DC=domain…

Note: The FRS subscriber object is deleted when the computer object is deleted, since it is a child of the computer account.

2. Use ADSIEdit to delete the FRS member object in CN=Domain System Volume (SYSVOL share),CN=file replication service,CN=system….
3. In the DNS console, use the DNS MMC to delete the cname (also known as the Alias) record in the _msdcs container.
4. In the DNS console, use the DNS MMC to delete the A (also known as the Host) record in DNS.
5. If the deleted computer was the last domain controller in a child domain and the child domain was also deleted, use ADSIEdit to delete the trustDomain object for the child in CN=System, DC=domain, DC=domain, Domain NC.

Links

Remove Data in Active Directory After an Unsuccessful Domain Controller Demotion – 216498

Remove Orphaned Domains from Active Directory – 230306