What does Windows error code 8011 (FRS_ERR_CHILD_TO_PARENT_COMM) mean?

Status / error code:		Category:

Constant name:
Source:		Operating System:
Description: legacy FRS cannot contact the parent domain controller.

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FRS_ERR_PARENT_AUTHENTICATION	FRS_ERR_PARENT_TO_CHILD_COMM

FRS_ERR_CHILD_TO_PARENT_COMM

The file replication service cannot communicate with the file replication service on the domain controller. The event log may have more information.

FRS_ERR_CHILD_TO_PARENT_COMM belongs to legacy File Replication Service (FRS). A diagnosis of this result must connect the condition to the producing API, current state, object identity, and first lower-level diagnostic.

This result is Win32 error 8011 (0x00001F4B) in legacy File Replication Service (FRS). Interpret it at the call that produced it and use the system message above as the immediate condition rather than as a complete root cause.

Where the result appears

processing legacy FRS communication from a child/member toward its parent domain controller.
managing a legacy FRS replica set or SYSVOL member.
handling a service, RPC, directory, staging, or database transition owned by NtFrs.
running an administrative tool against an environment whose FRS/DFSR migration state must be known.

State boundary to prove

This result applies to legacy FRS communication from a child/member toward its parent domain controller and does not by itself prove that the entire server, directory, disk, session, or application is unavailable. The state boundary to prove for this Win32 error is whether the local FRS service can send the required request to the selected parent and receive a valid response. Use child and parent identities, RPC endpoint and network trace, and DNS records and selected connection object as independent evidence. When evidence for this Win32 error disagrees, preserve timestamps and investigate the transition instead of selecting the most convenient value.

Likely causes

network or RPC connectivity fails in the child-to-parent direction.
DNS selects an unreachable parent.
firewall rules are asymmetric.
the parent FRS service is unavailable.

Diagnostic sequence

capture error 8011 immediately at the API boundary and record the operation that was attempted.
identify the exact owner of legacy FRS communication from a child/member toward its parent domain controller, including object generation, server, path, session, replica, or client context.
collect child and parent identities before restarting a service or changing configuration.
compare RPC endpoint and network trace with the documented or observed precondition.
correlate DNS records and selected connection object with the File Replication Service event log, Service Control Manager, Directory Service and Netlogon events, RPC diagnostics, and replica-set state.
determine whether side effects occurred and verify recovery after changing one responsible condition.

Evidence to collect

child and parent identities.
RPC endpoint and network trace.
DNS records and selected connection object.
FRS event logs on both systems.

Correlate it with the File Replication Service event log, Service Control Manager, Directory Service and Netlogon events, RPC diagnostics, and replica-set state. Keep the first detailed status even when a later wrapper translates it to error 8011; the first status often distinguishes transport, authorization, storage, schema, state, and application-integrity causes that share the same final Win32 result.

Handling, retry, and recovery

The recovery objective is to restore directional connectivity and parent service health, then verify a simple authenticated RPC operation before restarting replication work.

Retry it only after the recorded condition changes and completion state is known. Idempotent queries may be repeated after recovery, but mutations require a state check first; backoff cannot repair malformed input, corruption, missing structure, or policy rejection.

Telemetry and support fields

record child_to_parent_comm_api for the producing function or management operation.
record child_to_parent_comm_target for the file, log, session, replica, object, or server identity.
record child_to_parent_comm_state_before and child_to_parent_comm_requested_transition.
record child_to_parent_comm_first_status for the earliest lower-level diagnostic.

For support escalation involving it, retain decimal 8011, hexadecimal 0x00001F4B, the API, UTC time, target identity, and first subsystem-specific status. Include the smallest reproducible request and evidence that distinguishes this condition from nearby codes. In the context of it, frs is legacy technology. for sysvol, determine the domain’s actual migration state before applying an frs recovery procedure, because a domain already migrated to dfs replication has a different owner and recovery model.

Difference from nearby results

FRS_ERR_PARENT_TO_CHILD_COMM reports failure in the reverse direction

Practical validation scenario

A site firewall allows connections initiated by the DC but blocks member-to-DC dynamic RPC. Updating the directional rule lets the child contact its parent. The negative test should preserve the responsible condition and reproduce it; the recovery test should change only the identified cause, repeat the same operation, and verify both success and the absence of an unintended partial side effect.

Developer and administrator guidance

Administrators handling it must identify whether SYSVOL is actually owned by FRS or by DFS Replication before recovery. Developers and scripts should record directional partners, replica-set identity, and the first FRS event rather than treating a successful HTTP, RPC, or service-control call as proof that replication completed. Code that exposes it through RPC, JSON, REST, PowerShell, or another protocol should preserve the Win32 domain, decimal 8011, hexadecimal 0x00001F4B, and original component diagnostic.

References

Microsoft: Win32 system error range containing this code — official context relevant to it.
Microsoft: Migrate SYSVOL from FRS to DFS Replication — official context relevant to it.
Microsoft: Use BurFlags to reinitialize FRS — official context relevant to it.
Microsoft: AD DS troubleshooting — official context relevant to it.

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