Fixing Win32 Error 0x000006CC (RPC_S_DUPLICATE_ENDPOINT)

The error code 0x000006CC translates to RPC_S_DUPLICATE_ENDPOINT. This error message indicates that the RPC call failed because a duplicate endpoint was detected.

Understanding Endpoints in RPC:

• In RPC communication, endpoints represent communication channels between client and server applications. They are identified by a combination of factors like network address, protocol, and a program identifier (UUID).
• Ideally, each endpoint should be unique to avoid conflicts.

Reasons Behind RPC_S_DUPLICATE_ENDPOINT:

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

• Client-Side Configuration Issue: The client application might be attempting to create a duplicate endpoint, possibly due to code errors or incorrect configuration.
• Server-Side Endpoint Reuse (less common): In rare cases, the server-side implementation might be reusing an endpoint that is already in use, leading to a conflict.

Resolving RPC_S_DUPLICATE_ENDPOINT:

1. Review Client-Side Code:

   • Examine the client code responsible for creating RPC endpoints. Ensure it’s not accidentally creating endpoints with duplicate identifiers or using the same program identifier for multiple connections.

2. Verify RPC Configuration (if applicable):

   • If you have control over RPC client configuration, review settings related to endpoint creation. Ensure they are configured to avoid conflicts.

3. Server-Side Investigation (if possible):

   • If you have access to server administration, investigate if the server-side code might be reusing endpoints unexpectedly. This might require examining server logs or application behavior.

4. Restart RPC Services (if applicable):

   • In some cases, restarting RPC services on both the client and server machines can help clear any lingering endpoint registrations that might be causing conflicts.

5. Software Vendor Support:

   • If the issue persists, consider contacting the software vendor’s support for the program or service. They might have insights into specific endpoint usage requirements or troubleshooting steps for their software.

Additional Tips:

• Some RPC development tools or libraries might offer functionalities to manage and inspect RPC endpoints.
• Debuggers or logging mechanisms can help capture details about the endpoint being used in the client code and any error messages related to duplicate endpoint detection.

By understanding the concept of RPC endpoints and how duplicate endpoints can cause conflicts, you can identify the cause of this error. Reviewing client-side code, verifying RPC configuration (if applicable), investigating the server-side (if possible), restarting RPC services (if applicable), and contacting software vendor support can help address this error.