What does Windows error code 709 (ERROR_RECEIVE_PARTIAL_EXPEDITED) mean?

ERROR_RECEIVE_PARTIAL_EXPEDITED

What ERROR_RECEIVE_PARTIAL_EXPEDITED means

A transport delivered only part of an expedited data indication. In practical terms, this status belongs to fragmented expedited transport data: urgent or prioritized data requires additional receives before the expedited unit is complete.

Typical causes

• The expedited payload exceeds the supplied buffer
• The transport split the indication across multiple completions
• The client consumed only part of the available urgent data

How to investigate

1. Track expedited state separately from normal receive state
2. Preserve ordering and completion flags for the urgent unit
3. Exercise tests where expedited data is fragmented at every possible boundary

Developer guidance

The receiver must combine two concerns: partial delivery and expedited semantics. Losing either flag can corrupt protocol interpretation.

References

• Microsoft: System error codes 500–999