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ERROR_INVALID_FUNCTION
ERROR_INVALID_FUNCTION is Win32 system error 1 (0x00000001): “Incorrect function.” It means that the requested operation is not valid for the API path, object, device, filesystem, provider, or current state that received it. The word “function” refers to the requested system operation; it has nothing to do with the functional-programming paradigm.
Identify the operation that rejected the request
Save the exact Win32 API name and call GetLastError immediately after the failure. Record the target handle or path, flags, control code or operation type, device or filesystem type where relevant, and the state established by earlier calls. Frameworks may later translate error 1 into an HRESULT or exception and lose the original boundary.
Where to isolate the failure
Check whether the target actually supports the requested operation and whether the call is valid in its current state. For device and filesystem APIs, compare the same request with a known-supported target; for service or object APIs, verify the handle type and lifecycle. If a wrapper selected the wrong native API or passed an unsupported operation code, repeating the unchanged call will produce the same result.
Recovery and verification
Use the documented operation supported by the target, correct the call sequence or parameters, or choose a compatible provider/device. Verify the fix by rerunning the same minimal request and confirming both the return value and the intended state change. Do not treat a reboot or broad reinstall as proof unless the captured evidence identifies a state that those actions actually reset.
Official references
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