What does NTSTATUS 0xC01C0004 (STATUS_FLT_DISALLOW_FAST_IO) mean?

 
Previous Next
STATUS_FLT_INVALID_ASYNCHRONOUS_REQUEST STATUS_FLT_INVALID_NAME_REQUEST

STATUS_FLT_DISALLOW_FAST_IO

STATUS_FLT_DISALLOW_FAST_IO is a Filter Manager control status. It instructs the framework to force a fast-I/O attempt down the IRP path so normal minifilter and file-system processing can occur. It is not a status that a minifilter should return to Filter Manager or expose as an application-level error.

If it appears in tracing, inspect the fast-I/O decision and the corresponding IRP path. The important question is whether the driver returns one of the documented FLT_PREOP_CALLBACK_STATUS values and keeps the fast-I/O and IRP implementations consistent; manually returning this raw status breaks that callback contract.

Do not confuse it with

  • STATUS_FLT_IO_COMPLETE, which reports a lower filter completed an issued request.
  • STATUS_FLT_DISALLOW_FAST_IO, which redirects processing before a normal fast-I/O completion.
  • A failed read or write, which is represented by the final I/O status instead.

NTSTATUS reference | Filter Manager concepts | Writing callback routines


Looking for a different code? Search another status or error code.