What does Windows error code 1413 (ERROR_INVALID_INDEX) mean?

Status / error code:		Category:

Constant name:
Source:		Operating System:
Description: a USER32 class or window data index is outside the supported index space.

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ERROR_CLASS_HAS_WINDOWS	ERROR_INVALID_ICON_HANDLE

ERROR_INVALID_INDEX

The requested window-data index is invalid

Several USER32 APIs access attributes by numeric index: predefined negative constants select standard fields, while nonnegative offsets can address extra bytes reserved by the window class. These are contracts, not arbitrary array indexes.

A common defect is mixing a control-specific index with a generic window API, using byte offsets beyond cbWndExtra or cbClsExtra, or truncating an index in compatibility code. Dialog windows also reserve specific extra storage for dialog-manager data.

What to check

Identify the exact indexed API and print the symbolic index constant in diagnostics.
For custom extra bytes, compare the offset and stored type size with the class registration.
Use pointer-width APIs such as GetWindowLongPtr/SetWindowLongPtr where required.
Do not reuse dialog-private indexes as application storage.

ERROR_PRIVATE_DIALOG_INDEX is more specific when the numeric index targets storage reserved by the dialog manager.

References

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