What does NTSTATUS 0xC0000187 (STATUS_BACKUP_CONTROLLER) mean?

 
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STATUS_DEVICE_PROTOCOL_ERROR STATUS_LOG_FILE_FULL

STATUS_BACKUP_CONTROLLER

Route the operation to the role owner instead of retrying it on every controller

STATUS_BACKUP_CONTROLLER uses the PDC/BDC terminology of the Windows domain model. The Netlogon specification defines a backup domain controller as a controller that receives a synchronized copy of the domain database from the PDC. Modern Active Directory retains a single PDC emulator FSMO role holder for role-specific compatibility and password-related functions.

When this status appears, identify the exact operation and the controller that received it. Domain-controller discovery returning a reachable DC does not guarantee that the DC owns the PDC emulator role. A caller that requires a primary-only operation must locate or be directed to the role owner rather than assuming all controllers are interchangeable for that request.

Do not promote, demote, or seize FSMO roles merely because one API returned this status. First verify role ownership and connectivity to the current owner. Role transfer or seizure is an administrative recovery action with domain-wide consequences; a client-side routing bug or stale cached controller name should be corrected at the caller or discovery layer.

What to inspect

  • The operation being requested and whether its protocol/API documentation requires the PDC or PDC emulator.
  • The current PDC emulator role owner and whether the caller can discover and reach it.
  • Cached controller names, site selection, and failover logic that may keep sending the operation to a non-owner DC.

References


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