What does HRESULT 0x80041738 (FILTER_E_IN_USE) mean?

FILTER_E_IN_USE

Another process is using the document in an incompatible way

FILTER_E_IN_USE is HRESULT 0x80041738. Windows documents it as “The document is in use by another process.”

State represented by the HRESULT

This result belongs to opening content that is reachable but locked against the access mode required by the handler. A sharing or application-level lock prevents a stable filtering read.

Likely triggers

• At step 1, the producer saves with exclusive sharing
• At step 2, antivirus or conversion software temporarily owns the file
• At step 3, the handler requests stronger access than necessary
• At step 4, a stale lock remains after an abnormal process exit

Compare the failing case with a control that preserves locking process when available and changes only requested share and access modes; this prevents unrelated environment differences from dominating the test.

Data for diagnosis

• Locking process when available.
• Requested share and access modes.
• File identity and last-write time.
• Duration and recurrence of the lock.

Capture locking process when available before releasing objects, closing handles or reconnecting. Retain the raw HRESULT with requested share and access modes, component version, UTC timestamp and correlation ID.

Investigation order

1. Attempt a read with the same sharing semantics.
2. Identify the producer and whether the lock is part of an atomic save.
3. Wait for file size and write time to stabilize.
4. Avoid copying a half-written file merely to bypass the lock.

Preserve the component version and target identity, then alter only the condition described as a sharing or application-level lock prevents a stable filtering read.

Correct response

Use bounded delayed retry after the writer closes the document. Escalate persistent locks instead of spinning. Record whether opening content that is reachable but locked against the access mode required by the handler produced any content, update or state transition before returning.

Retry only after a concrete change in locking process when available or requested share and access modes.

Scope of the signal

It does not imply an ACL denial, missing file or malformed document. Without the call boundary for opening content that is reachable but locked against the access mode required by the handler, it also cannot identify which wrapper or configuration layer introduced the condition.

Related HRESULT values

FILTER_E_ALREADY_OPEN is internal filter-instance state; it concerns competing ownership of the source document.

Developer and administrator actions

• Record locking process when available with the returned HRESULT.
• In telemetry, correlate requested share and access modes with the target and component generation.
• For regression coverage, force the documented condition: a sharing or application-level lock prevents a stable filtering read.

Example in a pipeline

A desktop application rewrites a presentation under an exclusive lock. The indexer retries after the rename completes and receives stable bytes.

Official Microsoft references

• Microsoft: Content-Indexing values — official contract information relevant to this HRESULT.
• Microsoft: filter handlers in Windows Search
• Microsoft: IFilter interface
• Microsoft: testing filter handlers
• Microsoft: Filter-Interface values