Fixing Win32 Error 0x000006C9 (RPC_S_UNSUPPORTED_NAME_SYNTAX)

The error code 0x000006C9 translates to RPC_S_UNSUPPORTED_NAME_SYNTAX. This error message indicates that the RPC encountered a name syntax that is not supported by the name service being used.

Understanding Name Service Syntax Support:

• In RPC communication, clients sometimes use name services to locate servers. Different name services have varying rules and specifications for how server entries are formatted (syntax).
• The RPC_S_UNSUPPORTED_NAME_SYNTAX error occurs when the client attempts to use a server entry name that follows a syntax not supported by the underlying name service.

Reasons Behind RPC_S_UNSUPPORTED_NAME_SYNTAX:

There are a couple of reasons why you might encounter this error:

• Incorrect Name Service Assumption: The client code might be assuming a specific name service and its syntax for server entries, while the actual name service in use has a different format.
• Outdated Client Configuration (less common): In rare cases, if using an older RPC client configuration, it might be expecting a name service syntax that is no longer supported.

Resolving RPC_S_UNSUPPORTED_NAME_SYNTAX:

1. Verify Name Service Type:

   • Identify the specific name service being used for RPC calls on the system (e.g., Windows registry, LDAP).

2. Consult Program Documentation:

   • Refer to the documentation for the program or service you’re trying to access remotely. It might specify the expected name service and the format for server entry names.

3. Review RPC Configuration (if applicable):

   • If you have control over RPC client configuration, examine the settings related to the name service being used. Ensure it aligns with the actual name service on the system.

4. Software Vendor Support:

   • If the issue persists, consider contacting the software vendor’s support for the program or service. They might have insights into the required name service and its syntax for their software.

5. Name Service Specific Troubleshooting (advanced):

   • Consult documentation or resources specific to the name service being used (e.g., Windows registry documentation) to understand its supported syntax for server entries.

Additional Tips:

• Some RPC development tools or libraries might offer functionalities to specify the name service being used for lookups.
• Debuggers or logging mechanisms can help capture details about the name service and server entry name being used in the client code, allowing you to verify compatibility.

By understanding the concept of name service syntax and how it can vary between implementations, you can identify the cause of the unsupported syntax error. Verifying the name service type, consulting program documentation, reviewing RPC configuration (if applicable), contacting software vendor support, and performing name service specific troubleshooting (advanced) can help address this error.