Cannot Alter Down-Level Domain Name During Upgrade from Windows NT 4.0 to Windows 2000

You cannot change the NetBIOS domain name when you are upgrading a Microsoft Windows NT 4.0-based primary domain controller to Windows 2000. You can specify the Domain Name System (DNS) domain name, but you cannot alter the automatically created down-level NetBIOS domain name. You can change this name only after the upgrade and Dcpromo.exe processes have finished, by demoting and repromoting the server.

WARNING: Exercise caution if you determine that this process is necessary on an existing Windows 2000-based domain. The process of running Dcpromo to remove the computer from a domain, and then re-creating an Active Directory domain results in a total loss of all the computer account information and user account information for the domain. You must manually re-create all user account information and computer account information after using this process.