Knowledge

RPC_S_UNSUPPORTED_NAME_SYNTAX - 1737 (0x6C9)

The name syntax is not supported.

Updated: Feb 21, 2026

Technical Background

The RPC_S_UNSUPPORTED_NAME_SYNTAX error is a specific error code returned by the Remote Procedure Call (RPC) service in Windows. This error indicates that an operation was attempted with a name syntax that is not supported by the system or the application.

Error Details

  • Error Name: RPC_S_UNSUPPORTED_NAME_SYNTAX
  • Numeric Code: 1737
  • Hex Code: 0x6C9
  • Short Description: The name syntax is not supported.

This error typically occurs when an application attempts to use a name or identifier that the underlying system or service does not recognize or support. It can be encountered in various contexts, such as network communication or file operations involving RPC services.

Common Causes

  • Invalid Parameter Values: The operation was attempted with parameters that include unsupported name syntax.
  • Incorrect Object Type: The object type specified in the operation is not compatible with the expected name syntax.
  • Unsupported Operations: The operation being performed is not supported by the current context or configuration of the RPC service.

Real-World Context

This error can occur when an application tries to use a name format that is not recognized by the RPC service. For example, if an application attempts to register a service with a name syntax that is not compatible with the RPC service's expectations, this error will be returned.

Is This Error Critical?

The criticality of this error depends on the context in which it occurs. If the operation is non-critical and can be retried with valid parameters, the impact may be minimal. However, if the operation is part of a larger process that relies on successful RPC communication, the error could indicate a more significant issue.

How to Diagnose

  1. Review Operation Context: Ensure that the operation being performed is appropriate for the current context and configuration.
  2. Validate Parameters: Check that all parameters used in the operation are valid and correctly formatted according to the expected name syntax.
  3. Confirm Object Types: Verify that the object types specified in the operation are compatible with the expected name syntax.
  4. Verify Input Data: Ensure that any input data, such as service names or identifiers, are correctly formatted and supported by the RPC service.
  5. Check Limits or Constraints: Confirm that there are no system limits or constraints that could be causing the error.

How to Resolve

  1. Correct Parameter Usage: Adjust the parameters used in the operation to ensure they conform to the expected name syntax.
  2. Adjust Operation Context: Modify the context in which the operation is being performed if necessary, ensuring it aligns with the supported name syntax.
  3. Restore Data: If data corruption or incorrect formatting is suspected, restore the data to a known good state and retry the operation.
  4. Retry Operation with Valid Inputs: Attempt to perform the operation again using valid inputs that are compatible with the expected name syntax.

Developer Notes

Developers should ensure that all operations involving RPC services use names or identifiers that are supported by the service. This can be achieved through thorough testing and validation of input parameters, as well as adherence to documented naming conventions and standards.

Related Errors

  • RPC_S_INVALID_NAME: Indicates an invalid name was provided in the operation.
  • RPC_S_NAME_NOT_FOUND: The specified name could not be found or resolved.
  • RPC_S_NAME_COLLISION: A name collision occurred, preventing the operation from completing successfully.

FAQ

Q: What does RPC_S_UNSUPPORTED_NAME_SYNTAX mean?

A: This error indicates that an unsupported name syntax was used in a Remote Procedure Call (RPC) operation.

Q: How can I prevent this error?

A: Ensure that all names and identifiers used in RPC operations are compatible with the expected name syntax. Follow documented naming conventions and validate input parameters thoroughly.

Q: Can this error be critical?

A: The criticality depends on the context. If the operation is non-critical, it may not have significant impact. However, if part of a larger process, it could indicate a more serious issue.

Summary

The RPC_S_UNSUPPORTED_NAME_SYNTAX error indicates that an unsupported name syntax was used in an RPC operation. Developers should ensure that all operations use names and identifiers that are compatible with the expected syntax to avoid this error.