Knowledge

ERROR_INVALID_WINDOW_HANDLE - 1400 (0x578)

Invalid window handle.

Updated: Feb 21, 2026

Technical Meaning

The ERROR_INVALID_WINDOW_HANDLE (1400, 0x578) is a specific error code indicating that an invalid window handle was provided to a function or API. This error typically occurs when the system expects a valid window handle but receives one that does not exist or is improperly formatted.

Error Details

This error code is returned by various Windows APIs and functions that require a valid window handle as input. A window handle (HWND) is a unique identifier for a window in the Windows user interface, used to reference specific windows within applications.

Usage Context

The context in which this error occurs can vary widely depending on the function or API that was called. Common scenarios include:

  • Attempting to manipulate a window using an invalid handle.
  • Passing a handle to functions like SetWindowPos, SendMessage, or GetWindowText when the handle is not valid.

Developer Interpretation

When encountering this error, developers should ensure that all window handles passed to API functions are valid and correctly obtained. This typically involves:

  • Verifying that the window handle was properly created using functions like CreateWindowEx or FindWindow.
  • Ensuring that the handle is not stale (i.e., it has not been destroyed).
  • Checking for any race conditions where a window might be destroyed before its handle can be used.

Related Errors

  • ERROR_INVALID_HANDLE: A more generic error indicating an invalid handle in general, which may include window handles.
  • ERROR_WINDOW_NOT_FOUND: Specifically related to windows that do not exist.

FAQ

Q: What does the ERROR_INVALID_WINDOW_HANDLE mean?

A: It indicates that a function received an invalid window handle as input. This can occur if the handle is stale, incorrect, or has been destroyed before being used.

Q: How can I prevent this error from occurring?

A: Ensure that all window handles are valid and correctly obtained using appropriate API functions. Verify that the handle is not stale and that it corresponds to an existing window.

Summary

The ERROR_INVALID_WINDOW_HANDLE (1400, 0x578) is a specific error code indicating that an invalid window handle was provided to a function or API. Developers should ensure that all handles are valid and correctly obtained to avoid this error.