What does Windows error code 8634 (ERROR_DS_DOMAIN_NAME_EXISTS_IN_FOREST) mean?

 
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ERROR_DS_DRA_MISSING_KRBTGT_SECRET ERROR_DS_FLAT_NAME_EXISTS_IN_FOREST

ERROR_DS_DOMAIN_NAME_EXISTS_IN_FOREST

The domain name of the trusted domain already exists in the forest.

ERROR_DS_DOMAIN_NAME_EXISTS_IN_FOREST is a domain-specific Windows result.

Likely impact: Trust routing and authentication would be ambiguous if duplicate DNS names were admitted.

Typical causes

  • the domain already exists in the forest.
  • a stale trusted-domain object retains the name.
  • a migration reuses a production DNS namespace.
  • replication has not removed old trust metadata.

Troubleshooting steps

  1. Verify that the proposed trusted domain DNS name is unique across the forest trust namespace.
  2. Collect proposed DNS domain name and trustedDomain objects across the forest.

Useful evidence

  • Collect deletion and replication metadata.
  • Collect trust creation request.

Recovery and retry

Choose a unique domain name or clean up confirmed stale trust metadata after replication and ownership checks.

Related errors

ERROR_DS_FLAT_NAME_EXISTS_IN_FOREST checks the NetBIOS-style flat name; this code checks the DNS domain name

Example

A migration attempts to create a trust for a DNS name already represented by another domain. Renaming the incoming domain avoids an ambiguous trust namespace.

References


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