What does Windows error code 6843 (ERROR_DATA_LOST_REPAIR) mean?

 
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ERROR_DATA_LOST_REPAIR

Windows has discovered corruption in a file, and that file has since been repaired. Data loss may have occurred.

ERROR_DATA_LOST_REPAIR belongs to Windows file-system and storage integrity handling. 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 6843 (0x00001ABB) in Windows file-system and storage integrity handling. 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

  • opening a file after self-healing file-system repair.
  • receiving the result from storage repair or integrity handling.
  • recovering an application database or document after corruption.
  • validating data after an online repair operation.

State boundary to prove

This result applies to a file that Windows repaired after detecting corruption, with possible data loss 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 repaired file still contains all application-required records and remains semantically consistent. Use file identity and repaired ranges, file-system and storage events, and application checksums or database consistency results 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

  • damaged clusters or metadata required reconstruction.
  • a torn write left an invalid file range.
  • repair discarded unrecoverable bytes.
  • storage or memory corruption altered file content.
  • the file-system repair succeeded structurally but could not prove application integrity.

Diagnostic sequence

  1. capture error 6843 immediately at the API boundary and record the operation that was attempted.
  2. identify the exact owner of a file that Windows repaired after detecting corruption, with possible data loss, including object generation, server, path, session, replica, or client context.
  3. collect file identity and repaired ranges before restarting a service or changing configuration.
  4. compare file-system and storage events with the documented or observed precondition.
  5. correlate application checksums or database consistency results with the Windows System log, NTFS/ReFS events, storage-controller diagnostics, application integrity checks, and backup or replica logs.
  6. determine whether side effects occurred and verify recovery after changing one responsible condition.

Evidence to collect

  • file identity and repaired ranges.
  • file-system and storage events.
  • application checksums or database consistency results.
  • backup version and last known-good timestamp.
  • whether Windows reported bad clusters or a dirty volume.

Correlate it with the Windows System log, NTFS/ReFS events, storage-controller diagnostics, application integrity checks, and backup or replica logs. Keep the first detailed status even when a later wrapper translates it to error 6843; 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 quarantine the repaired copy, validate it with the owning application, restore missing data from backup or replica, and investigate the underlying storage before returning the file to production.

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 data_lost_repair_api for the producing function or management operation.
  • record data_lost_repair_target for the file, log, session, replica, object, or server identity.
  • record data_lost_repair_state_before and data_lost_repair_requested_transition.
  • record data_lost_repair_first_status for the earliest lower-level diagnostic.

For support escalation involving it, retain decimal 6843, hexadecimal 0x00001ABB, 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, the code identifies a file-system result, but the decisive evidence often comes from the lower storage layer and from application-level validation of the affected data.

Difference from nearby results

ERROR_FILE_CORRUPT reports corruption that prevents use; it says Windows repaired the file but warns that repair may have discarded data.

Practical validation scenario

A document opens after NTFS repairs a damaged extent. The application-level checksum no longer matches, so the administrator restores the last backup and retires the failing disk rather than treating the repair as complete. 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 should prioritize data preservation and hardware evidence before repair. Developers should separate structural file-system success from application-level integrity, because a readable or repaired file can still be semantically incomplete. Code that exposes it through RPC, JSON, REST, PowerShell, or another protocol should preserve the Win32 domain, decimal 6843, hexadecimal 0x00001ABB, and original component diagnostic.

References

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