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# applicationWillResignActive(_:)

Tells the delegate that the app is about to become inactive and will lose focus.

```
@MainActor optional func applicationWillResignActive(_ notification: Notification)
```

## Parameters

`notification`

A notification named [`willResignActiveNotification`](/documentation/AppKit/NSApplication/willResignActiveNotification). Calling the <doc://com.apple.documentation/documentation/Foundation/NSNotification/object> method of this notification returns the `NSApplication` object itself.

## Discussion

---

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