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hrCommunicationError
Why this result matters
For hrCommunicationError, this code narrows the investigation to one engine boundary and should not be flattened into a generic exception. The decisive boundary is the local backup protocol failed after the operation began exchanging control or file data.
The stored Value is 0xC7FF000D (facility-specific HRESULT). The HRESULT carries failure severity, so output state must be treated according to the individual API contract. The legacy this result name comes from the Windows Directory Service backup/restore message header.
The first useful distinction is that hrCouldNotConnect is normally an establishment failure; this result indicates a communication breakdown during the local workflow. Start by capture the failing API, bytes transferred, RPC and Win32 status, service events, HBC state, and last successfully closed file. That separates a reproducible incident from a later generic cleanup or service error.
Do not confuse it with
This result specifically means that hrCouldNotConnect is normally an establishment failure; it indicates a communication breakdown during the local workflow. Related values below can appear in the same workflow but require a different response:
hrCouldNotConnect | the backup client could not establish the required session with the selected server or running Directory Service |
|---|---|
hrBFPageNotFound | the requested page was not present in the buffer-manager context used by the operation |
hrRestoreMapExists | a restore map is already registered for the component while the caller attempts to add another mapping |
Keep the original constant and hexadecimal value in telemetry. Replacing it with “backup failed” or “database warning” removes the state information needed to select the next legal API call.
Forensic checklist
Preserve the first result before retries, cleanup, service restart, or file replacement changes the evidence. The diagnostic record should identify the exact API phase and the owner of every handle or artifact involved.
- Code-specific observation: capture the failing API, bytes transferred, RPC and Win32 status, service events, HBC state, and last successfully closed file.
- Security context and privilege: record it together with it and the timestamp of the first occurrence.
- Last completed file boundary: record it together with it and the timestamp of the first occurrence.
- Server resolution and service state: record it together with it and the timestamp of the first occurrence.
- RPC and Win32 status: record it together with it and the timestamp of the first occurrence.
Use hashes, lengths, IDs, generation numbers, and redacted samples instead of copying directory contents or sensitive database values into routine logs. For this it investigation, a complete provenance chain is often more useful than a second automatic retry.
Objects and state involved
| Diagnostic layer | Directory Service state, RPC connectivity, authentication, and the HBC transport |
|---|---|
| Relevant API surface | DsIsNTDSOnline, DsSetAuthIdentity, DsBackupPrepare, and subsequent file transfer calls |
| Code-specific boundary | the local backup protocol failed after the operation began exchanging control or file data |
| Narrow corrective direction | abort the context, correct the transport or service fault, and restart the backup so file boundaries are unambiguous |
The legacy API requires the directory service to be running for backup and offline for restore., transport failure can invalidate the context and make partial file data unusable as a set.
Actions that can make diagnosis worse
- do not resume in the middle of a file without a protocol guarantee.
- do not report a connectivity problem as database corruption.
- do not discard the first lower-level Win32, RPC, or JET result merely because a later cleanup call returned a more familiar error.
Validation after correction
- Record it,
0xC7FF000D, the API name, the current phase, and all live context or file owners. - Verify the decisive condition by capture the failing API, bytes transferred, RPC and Win32 status, service events, HBC state, and last successfully closed file.
- Apply only the narrow correction: abort the context, correct the transport or service fault, and restart the backup so file boundaries are unambiguous.
- After it, recreate any context invalidated by the failure; do not carry stale HBC, cursor, file, or restore-map state into the retry.
- repeat the smallest non-destructive test that reaches the same boundary, then verify both the return value and the resulting file, cursor, backup, or database state.
Acceptance criteria for a fix
A useful regression test for this HRESULT should force the condition “the local backup protocol failed after the operation began exchanging control or file data”, call one documented API transition, and assert the exact HRESULT. The corrected the case should change only the decisive precondition and should verify cleanup as well as the primary output. For the result backup or restore path, also prove that the resulting set can be enumerated and that no file handle or context remains active after finalization.
Technical references
- AD backup walkthrough — API ordering, file semantics, warning/error interpretation, or recovery behavior relevant to it.
- DsBackupPrepare contract
- AD backup errors
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