Could not promote new domain controller.

Hi lannyzhang,

Based on the information you provided and additional resources, here are some suggestions:

1. Adprep /forestprep and /domainprep: Ensure you use the correct version of adprep for your system (x64 or x32 disc).

2. Prerequisites and Permissions: Confirm that the server meets system requirements, has the AD DS role installed, and the administrator has appropriate group memberships.

3. DNS Settings: Check and correct any incorrect or incompatible DNS settings that may lead to DCPROMO failures.

4. Replication Failures: Resolve any replication issues with old domain controllers, removing orphaned ones if necessary.

5. Check FSMO Roles: Verify the validity of FSMO role holders using Netdom query fsmo.

6. Rebuild _msdcs zone: Consider rebuilding the _msdcs zone if promotion issues persist.

Upgrade domain controllers to a newer version of Windows Server | Microsoft Learn

[SOLVED] Unable to promote windows server 2019 to a domain controller - Active Directory & GPO (spiceworks.com)

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