How to remove data in Active Directory after an unsuccessful domain controller demotion

1. Click Start, point to Programs, point to Accessories, and then click Command Prompt.
2. At the command prompt, type ntdsutil, and then press ENTER.
3. Type metadata cleanup, and then press ENTER. Based on the options given, the administrator can perform the removal, but additional configuration parameters must be specified before the removal can occur.
4. Type connections and press ENTER. This menu is used to connect to the specific server where the changes occur. If the currently logged on user does not have administrative permissions, different credentials can be supplied by specifying the credentials to use before making the connection. To do this, type set creds DomainNameUserNamePassword, and then press ENTER. For a null password, type null for the password parameter.
5. 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

6. Type quit, and then press ENTER. The Metadata Cleanup menu appears.
7. Type select operation target and press ENTER.
8. Type list domains and press ENTER. A list of domains in the forest is displayed, each with an associated number.
9. Type select domain number and press ENTER, where number is the number associated with the domain the server you are removing is a member of. The domain you select is used to determine whether the server being removed is the last domain controller of that domain.
10. Type list sites and press ENTER. A list of sites, each with an associated number, appears.
11. Type select site number and press ENTER, where number is the number associated with the site the server you are removing is a member of. You should receive a confirmation listing the site and domain you chose.
12. Type list servers in site and press ENTER. A list of servers in the site, each with an associated number, is displayed.
13. 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 System (DNS) host name, and the location of the server's computer account you want to remove.
14. Type quit and press ENTER. The Metadata Cleanup menu appears.
15. Type remove selected server and press ENTER. You should receive confirmation that the removal completed successfully. If you receive the following error message, the NTDS Settings object may already be removed from 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.

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

    
    Note You may also see this error when you try to bind to the domain controller that will be removed. Ntdsutil has to bind to a domain controller other than the one that will be removed with metadata cleanup.

Type quit, and then press ENTER at each menu quit the Ntdsutil utility. You should receive confirmation that the connection disconnected successfully. Remove the cname record in the _msdcs.root domain of forest zone in DNS. Assuming that DC will be reinstalled and re-promoted, a new NTDS Settings object is created with a new GUID and a matching cname record in DNS. You do not want the DCs that exist to use the old cname record.
As best practice, you should delete the host name 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. In the DNS console, use the DNS MMC to delete the A record in DNS. The A record is also known as the Host record. To delete the A record, right-click the A record, and then click Delete. Also, delete the cname record in the _msdcs container. To do this, expand the _msdcs container, right-click cname, and then click Delete.
Important If this is a DNS server, remove the reference to this DC under the Name Servers tab. To do this, in the DNS console, click the domain name under Forward Lookup Zones, and then remove this server from the Name Servers tab.
Note If you have reverse lookup zones, also remove the server from these zones. If the deleted computer is 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. To do this, follow these steps: Click Start, click Run, type adsiedit.msc, and then click OK Expand the Domain NC container. Expand DC=Your Domain, DC=COM, PRI, LOCAL, NET. Expand CN=System. Right-click the Trust Domain object, and then click Delete. Use Active Directory Sites and Services to remove the domain controller. To do this, follow these steps: Start Active Directory Sites and Services. Expand Sites. Expand the server's site. The default site is Default-First-Site-Name. Expand Server. Right-click the domain controller, and then click Delete. When you use DFS Replication in Windows Server 2008 and in later versions, the current version of Ntdsutil.exe does not clean up the DFS Replication object. In this case, you can use Adsiedit.msc to correct the DFS Replication objects for Active Directory Domain Services (AD DS) manually. To do this, follow these steps: Logon a domain controller as a domain administrator in the affected domain. Start Adsiedit.msc. Connect to the default naming context. Locate the following DFS Replication topology container: CN=Topology,CN=Domain System Volume,CN=DFSR-Globalsettings,CN=System,DC=Your Domain,DC=Domain Suffix Delete the msDFSR-Member CN object that has the old computer name.