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# willUpdateNotification

Posted at the start of the [`updateWindows()`](/documentation/AppKit/NSApplication/updateWindows()) method to indicate that the app is about to update its windows.

```
class let willUpdateNotification: NSNotification.Name
```

## Discussion

The notification object is [`shared`](/documentation/AppKit/NSApplication/shared). This notification doesn’t contain a `userInfo` dictionary.  The system posts this notification on the main actor.

To observe this notification using Swift concurrency, use [`NSApplication.WillUpdateWindowsMessage`](/documentation/AppKit/NSApplication/WillUpdateWindowsMessage).

---

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