You installed Windows NT Server as a Backup Domain Controller (BDC) but accidentally joined the wrong domain name during setup. What is the correct remediation?

Introduction / Context:
In Windows NT domain architecture, a Backup Domain Controller (BDC) is tightly bound to its domain at installation. Unlike a stand-alone server or member server, you cannot simply rename the domain affiliation of a BDC post-install. This question tests knowledge of immutable domain bindings in NT 4.0 era setups.

Given Data / Assumptions:

• Server role: Backup Domain Controller.
• Wrong domain name specified during setup.
• Goal: associate the BDC with the correct domain.

Concept / Approach:

A BDC maintains a secure trust relationship, SAM database synchronization, and role metadata bound to a specific domain. NT does not support switching a BDC to another domain via GUI, registry edits, or repair utilities. The supported method is to reinstall NT Server and join the correct domain during setup so that security identifiers and replication partnerships are established properly.

Step-by-Step Solution:

Verification / Alternative check:

Microsoft deployment guidance for NT domains explicitly states that BDC domain membership cannot be changed after installation without reinstalling, confirming this remedy.

Why Other Options Are Wrong:

Control Panel / Registry / Emergency Repair Disk: None can rebind a BDC to a different domain; attempts lead to inconsistent security and replication state.

None of the above: Incorrect because reinstall is correct.

Common Pitfalls:

Trying to hack the registry to change domain affiliation; promoting to PDC or demoting is not supported in NT 4.0 like modern Active Directory.

Final Answer:

Reinstall Windows NT Server