The error code 0x00000587 translates to ERROR_PRIVATE_DIALOG_INDEX. Unlike the other errors you’ve asked about, this one doesn’t have a publicly documented meaning or explanation from Microsoft. There are two main sources of information that might be helpful:

1. HRESULT.info: This website provides a listing of error codes, including 0x00000587. However, their explanation mentions “Using private DIALOG window words.” This isn’t a commonly used term in Win32 API documentation, so it might not be directly applicable. https://neurotechnics.com/blog/fix-symbolic-link-cannot-be-followed/

2. Free Pascal Unit (Jedi): The error code appears in the documentation for a unit called “winunits_jedi” within the Free Pascal compiler. In this context, it seems to be an internal error code used by that specific unit. https://www.freepascal.org/faq.html

Without a definitive explanation from Microsoft, it’s difficult to pinpoint the exact cause of this error in your program. Here are some general approaches you can take:

1. Search Online Forums and Communities: Search online forums and communities frequented by programmers using the Win32 API or Free Pascal. You might find discussions or solutions related to this specific error code from other developers who have encountered it.

2. Context and Debugging: If you can provide more context about the situation where this error occurs (programming language, libraries used, actions leading to the error), it might be possible to offer more specific troubleshooting advice. Debugging tools can also help identify the section of your code where the error originates.

3. Consider Alternative Approaches: If you’re unsure about the cause of the error and can’t find a clear solution, consider alternative approaches to achieve the functionality you’re aiming for. There might be other Win32 API functions or techniques that don’t involve using “private DIALOG window words” (if that’s indeed the issue).

4. Review Free Pascal Documentation (if applicable): If you’re using Free Pascal with the “winunits_jedi” unit, carefully review the documentation for that unit. It might provide clues about how to avoid encountering this internal error code.

Remember that due to the lack of official documentation, fixing this error might require more investigation and exploration of alternative solutions compared to the other Win32 errors you’ve inquired about.