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hrInvalidBackupSequence
Why this result matters
hrInvalidBackupSequence means backup APIs were called in an order that violates the ESE external-backup state machine.
The stored value is 0xC8000209 (negative JET error -521; -521). Current ESE documentation uses JET_errInvalidBackupSequence for the corresponding published JET condition.
The first useful distinction is that for example, log enumeration advances the state so database files can no longer be opened in the earlier phase. Start by logging the ordered API trace, open file handles, transition to log enumeration, and result of every close/end call.
Do not confuse it with
This result specifically means that for example, log enumeration advances the state so database files can no longer be opened in the earlier phase. Related values below can appear in the same workflow but require a different response:
hrBackupNotAllowedYet | the instance is temporarily in a state where a backup cannot begin safely |
|---|---|
hrBackupInProgress | an external backup session is already active for the relevant ESE instance |
hrNoBackupDirectory | the external-backup operation has no destination directory configured for its temporary or copied artifacts |
Forensic checklist
- Code-specific observation: log the ordered API trace, open file handles, transition to log enumeration, and result of every close/end call.
- Open backup file handles: capture the value and timestamp from the first occurrence.
- Database/log enumeration transition: capture the value and timestamp from the first occurrence.
- Ordered API trace: capture the value and timestamp from the first occurrence.
- Instance and active backup owner: capture the value and timestamp from the first occurrence.
Objects and state involved
| Diagnostic layer | the ESE external-backup state machine and its single active session |
|---|---|
| Relevant API surface | JetBeginExternalBackup, JetGetAttachInfo, JetOpenFile/ReadFile/CloseFile, JetGetLogInfo, and JetEndExternalBackup |
| Code-specific condition | backup APIs were called in an order that violates the ESE external-backup state machine |
| Narrow corrective direction | discard the context and repeat the documented begin, enumerate, open/read/close, logs, and end sequence |
Database files are enumerated and copied before the backup advances to the log-file phase. The engine tracks outstanding backup file handles and rejects calls made in the wrong phase.
Actions that can make diagnosis worse
- Do not continue using a context after a sequence failure.
- Do not omit the final end/abort path.
Validation after correction
- Record it,
0xC8000209, the API name, the current phase, and all live context or file owners. - Verify the condition by logging the ordered API trace, open file handles, transition to log enumeration, and result of every close/end call.
- Apply only the targeted fix: discard the context and repeat the documented begin, enumerate, open/read/close, logs, and end sequence.
Acceptance criteria for a fix
A useful regression test should force the condition “backup APIs were called in an order that violates the ESE external-backup state machine”, call one documented API transition, and assert the exact HRESULT.
Technical references
- Begin external backup — API ordering, file semantics, warning/error interpretation, or recovery behavior relevant to this HRESULT.
- Enumerating backup logs
- End external backup
- Microsoft JET_ERR enumeration
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