| Previous | Next |
| ERROR_APPEXEC_HOST_ID_MISMATCH | ERROR_WINS_INTERNAL |
ERROR_IO_REISSUE_AS_CACHED
Reissue the operation as cached I/O.
ERROR_IO_REISSUE_AS_CACHED is Win32 status 3950 (0xF6E). Microsoft’s public system-code text is an instruction to reissue the operation as cached I/O. It is generally a control result inside an I/O stack rather than a user-facing disk failure, so applications should not blindly loop on the same request or display “file corrupt.”
Why an I/O path may request reissue
- a filesystem, filter, cache, or storage path cannot satisfy the current noncached form and selects a cached route
- alignment, buffering, mapping, compression, encryption, sparse, or metadata behavior requires a different I/O mode
- an internal layer has already normalized state and expects the caller within that stack to restart through cache semantics
- a driver or wrapper incorrectly leaks an internal retry status to a boundary that does not implement the reissue contract
- custom I/O code retries without changing mode and creates a busy loop
I/O evidence
Record the API or driver boundary, file/device path category, operation type, offset and length, cached/noncached and synchronous/asynchronous flags, alignment, filesystem and volume, filter/driver stack, request ID, first status, retry mode, and completion outcome. Avoid logging file content and sensitive full paths.
Diagnostic sequence
Identify the layer that returned 3950 and whether its documented contract expects the immediate caller to reissue. Compare the original open flags and request parameters with the cached variant. Use filesystem and filter tracing to ensure the operation is not repeatedly bouncing between modes.
If a user-mode API unexpectedly exposes the code, capture a minimal reproduction and inspect third-party filters, drivers, and wrappers. Do not assume that reopening with arbitrary buffering flags is safe; noncached I/O can be chosen for durability, coherency, or device-specific reasons.
Recovery and implementation safety
Within a component that owns the documented contract, rebuild the request as cached I/O once and preserve cancellation, offset, and completion semantics. At an unsupported boundary, fail safely and escalate to the owning driver or filesystem rather than inventing a retry protocol.
Guard reissue with a mode/state flag and retry limit, maintain one logical-operation correlation ID, and test short I/O, cancellation, flush, and concurrent access. Administrators should update or isolate faulty storage filters when the status escapes repeatedly.
Difference from ERROR_RETRY
ERROR_RETRY asks for another attempt without prescribing an I/O mode. Status 3950 specifically directs the owning I/O path to reissue as cached I/O, so repeating the unchanged request does not satisfy it.
Example
A filesystem filter receives a noncached request it cannot process in that form and returns 3950 to its expected caller. The caller rebuilds one cached request and completes it. A buggy wrapper that resends the original noncached request indefinitely would spin.
References
Looking for a different code? Search another status or error code.