We are observing an issue where the iOS Notification Service Extension (NSE) is terminated by the system during startup, before either didReceive(_:withContentHandler:) or serviceExtensionTimeWillExpire(_:) is invoked. When this occurs, the notification is delivered without modification (for example, an encrypted payload is shown to the user). System logs frequently contain the message “Extension will be killed because it used its runtime in starting up”. During testing, we observed that CPU-intensive operations or heavy initialization performed early in the extension lifecycle — especially inside init() or directly on the main thread in didReceive often cause the system to kill the NSE almost immediately. These terminations happen significantly earlier than the commonly observed ~30-second execution window where the OS normally invokes serviceExtensionTimeWillExpire(_:) before ending the extension. When these early terminations occur, there is no call to the expiry handler, and the process appears to be forcefully shut down. Moving the same operations to a background thread changes the behavior: the extension eventually expires around the usual 30-second window, after which the OS calls serviceExtensionTimeWillExpire(_:). We also observed that memory usage plays a role in early termination. During tests involving large memory allocations, the system consistently killed the extension once memory consumption exceeded a certain threshold (in our measurements, this occurred around 150–180 MB). Again, unlike normal time-based expiration, the system did not call the expiry handler and no crash report was produced. Since Apple’s documentation does not specify concrete CPU, memory, or startup-cost constraints for Notification Service Extensions or any other extensions beyond the general execution limit, we are seeking clarification and best-practice guidance on expected behaviors, particularly around initialization cost and the differences between startup termination. NSE Setup: class NotificationService: UNNotificationServiceExtension { static var notificationContentHandler: ((UNNotificationContent) -> Void)? static var notificationContent: UNMutableNotificationContent? static var shoudLoop = true override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) { NotificationService.notificationContentHandler = contentHandler NotificationService.notificationContent = request.content.mutableCopy() as? UNMutableNotificationContent NotificationService.notificationContent!.title = "Weekly meeting" NotificationService.notificationContent!.body = "Updated inside didReceive" // Failing scenarios } override func serviceExtensionTimeWillExpire() { NotificationService.shoudLoop = false guard let handler = NotificationService.notificationContentHandler, let content = NotificationService.notificationContent else { return } content.body = "Updated inside serviceExtensionTimeWillExpire()" handler(content) } }

I’m testing remote push notifications on macOS, and although notifications are received and displayed correctly, my Notification Service Extension (NSE) never gets invoked. The extension is properly added as a target in the same app, uses the UNNotificationServiceExtension class, and implements both didReceive(_:withContentHandler:) and serviceExtensionTimeWillExpire(). I’ve also set "mutable-content": 1 in the APNS payload, similar to how it works on iOS — where the same code correctly triggers the NSE. On macOS, however, there’s no sign that the extension process starts or the delegate methods are called. import UserNotifications class NotificationService: UNNotificationServiceExtension { override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) { let modified = (request.content.mutableCopy() as? UNMutableNotificationContent) modified?.title = "[Modified] " + (modified?.title ?? "") contentHandler(modified ?? request.content) } override func serviceExtensionTimeWillExpire() { // Called if the extension times out before finishing } } And the payload used for testing: { "aps": { "alert": { "title": "Meeting Reminder", "body": "Join the weekly sync call" }, "mutable-content": 1 }, "MEETING_ORGANIZER": "Alex Johnson" } Despite all correct setup steps, the NSE never triggers on macOS (while working fine on iOS). Can anyone confirm whether UNNotificationServiceExtension is fully supported for remote notifications on macOS, or if additional configuration or entitlement is needed?

For a macOS GUI application (with a UIKit or AppKit entry point), I want to reliably capture diagnostic logs sent to stderr — especially useful when the app is launched from a terminal script or runs in the background, and traditional GUI elements (like alert dialogs) may not be viable. This is to log startup failures or even success messages for later inspection. However, when the app is launched via open MyApp.app, stderr redirection like open MyApp.app 2> log.txt does not capture any output — the file is created, but remains empty. The only way I can capture stderr reliably is by bypassing the bundle and directly launching the binary inside with ./MyApp.app/Contents/MacOS/MyApp 2> ~/log.txt This logs as expected, but is not the user-friendly or typical way to launch apps on macOS. Double-clicking the app in Finder also does not show any stderr output. Is there any recommended or supported way to redirect or access stderr output when launching a .app bundle via open, or any best practice for logging critical failures from a GUI app when terminal output isn't visible?