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# willLaunchApplicationNotification

A notification that the workspace posts when the Finder is about to launch an app.

```
class let willLaunchApplicationNotification: NSNotification.Name
```

## Discussion

The notification object is the shared `NSWorkspace` instance. The `userInfo` dictionary contains the [`applicationUserInfoKey`](/documentation/AppKit/NSWorkspace/applicationUserInfoKey) key with a corresponding instance of [`NSRunningApplication`](/documentation/AppKit/NSRunningApplication) that represents the affected app.

The system doesn’t post this notification for background apps or for apps that have the `LSUIElement` key in their `Info.plist` file. If you want to know when all apps (including background apps) launch or terminate, use key-value observing to monitor the value that returns from the [`runningApplications`](/documentation/AppKit/NSWorkspace/runningApplications) method.

> Important:
> To receive this notification, use ``doc://com.apple.appkit/documentation/AppKit/NSWorkspace/notificationCenter`` to register for it. If you use a different notification center to register, you won’t receive the notification.

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

---

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