Knowledge

RPC_S_PROTOCOL_ERROR - 1728 (0x6C0)

A remote procedure call (RPC) protocol error occurred.

Updated: Feb 21, 2026

Overview

The error code RPC_S_PROTOCOL_ERROR (1728, 0x6C0) indicates that a remote procedure call (RPC) protocol error has occurred. This error is specific to the context of RPC operations and suggests that there was an issue with the protocol being used during the execution of an RPC request or response.

Technical Meaning

This error code is returned by the Windows API when an RPC operation fails due to a protocol-related issue. It can occur in various scenarios, such as network communication problems, incorrect protocol versions, or issues related to the structure and format of the data being exchanged between the client and server.

Error Details

The RPC_S_PROTOCOL_ERROR error code is typically used when the RPC runtime detects that the protocol being used for an RPC operation does not conform to the expected standards. This can include issues such as incorrect message formats, unsupported protocol versions, or problems with the network stack that affect the integrity of the data being transmitted.

Usage Context

This error code is relevant in scenarios where RPC operations are performed over a network. It may be encountered when using various Windows APIs and services that rely on RPC for communication between processes or machines. Developers should consider this error as an indication that there might be issues with the underlying protocol stack, network configuration, or data being exchanged.

Developer Interpretation

When encountering RPC_S_PROTOCOL_ERROR, developers should focus on validating the protocol settings and ensuring that all parties involved in the RPC operation are using compatible versions of the protocol. This may involve checking the following:

  • Network connectivity and stability
  • Protocol version compatibility between client and server
  • Correctness of data formats and structures being exchanged
  • Configuration of network components such as firewalls or proxies

    Related Errors

  • RPC_S_SERVER_UNAVAILABLE (1725, 0x6B9): Indicates that the RPC server is not available.
  • RPC_S_CALL_FAILED (1738, 0x6E6): General failure of an RPC call.
  • WSAEPROTONOSUPPORT (10048, WSAEPROTONOSUPPORT): The protocol option specified in the socket option is not supported by the underlying transport.

    FAQ

    Q: What does RPC_S_PROTOCOL_ERROR mean?

    A: It indicates that a remote procedure call (RPC) operation failed due to a protocol-related issue. This could be caused by network problems, incorrect protocol versions, or issues with data being exchanged.

    Q: How can I resolve this error?

    A: Ensure that all parties involved in the RPC operation are using compatible protocol versions and correct data formats. Check network connectivity and configuration for any potential issues.

    Summary

    The RPC_S_PROTOCOL_ERROR (1728, 0x6C0) is a specific error code indicating an issue with the protocol used during an RPC operation. Developers should focus on validating protocol settings and ensuring compatibility between client and server to resolve this error.