ERROR_INVALID_FILTER_PROC - 1427 (0x593)
Invalid hook procedure.
Updated: Feb 21, 2026
Technical Meaning
The error code ERROR_INVALID_FILTER_PROC with the numeric value of 1427 or hexadecimal 0x593 indicates that a hook procedure, which is a function used to intercept and modify system calls, was called incorrectly.
Error Details
This error typically occurs when a filter function, such as those used in device drivers or system hooks, does not adhere to the expected behavior. Specifically, it suggests that the filter function did not return the correct value or did not follow the required protocol for handling system calls.
Usage Context
This error is commonly encountered in scenarios where custom hook procedures are implemented within a Windows application or driver. It can also appear when using certain APIs that rely on callback functions to process events or data.
Developer Interpretation
Developers should interpret this error as an indication that the filter function did not behave as expected. This could be due to incorrect parameter handling, failure to return valid values, or improper implementation of the hook procedure itself.
Related Errors
ERROR_INVALID_PARAMETER(1402)ERROR_BAD_EXE_FORMAT(193)STATUS_UNSUCCESSFUL(80000000)
FAQ
Q: What does the error ERROR_INVALID_FILTER_PROC mean?
A: It indicates that a hook procedure was called incorrectly, likely due to incorrect parameter handling or improper implementation.
Q: How can I resolve this issue?
A: Ensure that your filter function adheres to the expected behavior and returns valid values. Review the documentation for the specific API or driver you are working with to understand the correct implementation details.
Summary
The ERROR_INVALID_FILTER_PROC error code is a specific technical indicator of incorrect behavior in hook procedures within Windows applications or drivers. Developers should carefully review their implementation to ensure it complies with the expected protocol and returns valid values.