Windows error 1418 (ERROR_CLIPBOARD_NOT

Status / error code:		Category:

Constant name:
Source:		Operating System:
Description: the calling thread attempted a clipboard operation without an active OpenClipboard session.

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ERROR_NO_WILDCARD_CHARACTERS	ERROR_HOTKEY_NOT_REGISTERED

ERROR_CLIPBOARD_NOT_OPEN

The thread has not opened the clipboard

Clipboard data access is serialized. A window or thread first calls OpenClipboard, performs the supported clipboard operations, and then calls CloseClipboard. Only one window can have the clipboard open at a time.

This error usually comes from lifecycle structure rather than data format. A helper may call GetClipboardData or EmptyClipboard after an earlier scope already closed the clipboard. Delayed rendering is a special case: while processing WM_RENDERFORMAT, the owner must not open the clipboard because the requester already has it open.

What to check

Keep open/close ownership in one scope and one thread.
Check every early-return path for an unmatched CloseClipboard.
Do not retry data operations until OpenClipboard itself succeeded.
Handle delayed-rendering messages according to their distinct clipboard-open rules.

This status does not say another application currently owns the open lock; it says the caller has no valid open-clipboard context for the attempted operation.

References

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