I'm troubleshooting a crash I do not understand.
I have a queue called DataQueue which never has anything dispatched to it - it's the sample buffer delegate of an AVCaptureVideoDataOutput. It can call DispatchQueue.main.sync to do some work on the main thread.
It works fine no matter what we test, but has some crashes in the field that I need to fix. Here's it crashing:
AppleCameraDataDelegate.dataQueue
0 libsystem_kernel.dylib 0x7bdc __ulock_wait + 8
1 libdispatch.dylib 0x4a80 _dlock_wait + 52
2 libdispatch.dylib 0x486c _dispatch_thread_event_wait_slow$VARIANT$mp + 52
3 libdispatch.dylib 0x113d8 __DISPATCH_WAIT_FOR_QUEUE__ + 332
4 libdispatch.dylib 0x10ff0 _dispatch_sync_f_slow + 140
The main thread isn't doing something I asked it to, but appears to be busy:
Thread
0 libsystem_kernel.dylib 0x71a4 __psynch_cvwait + 8
1 libsystem_pthread.dylib 0x7fd8 _pthread_cond_wait$VARIANT$mp + 1232
2 grpc 0x2cb670 gpr_cv_wait + 131 (sync.cc:131)
3 grpc 0x119688 grpc_core::Executor::ThreadMain(void*) + 225 (executor.cc:225)
4 grpc 0x2e023c grpc_core::(anonymous namespace)::ThreadInternalsPosix::ThreadInternalsPosix(char const*, void (*)(void*), void*, bool*, grpc_core::Thread::Options const&)::'lambda'(void*)::__invoke(void*) + 146 (thd.cc:146)
5 libsystem_pthread.dylib 0x482c _pthread_start + 104
6 libsystem_pthread.dylib 0xcd8 thread_start + 8
Can anyone help me understand why this is a crash?
Processes & Concurrency
RSS for tagDiscover how the operating system manages multiple applications and processes simultaneously, ensuring smooth multitasking performance.
Selecting any option will automatically load the page
Post
Replies
Boosts
Views
Activity
We have an application that sets a code signing requirement on a XPC connection between a File Provider extension and the main application. Only with a specific Developer ID certificate <DEVELOPER_ID_TEAM_IDENTIFIER> that designated requirement is not accepted and the application crashes with EXC_CRASH (SIGABRT) and the stacktrace
Thread 1 Crashed:: Dispatch queue: com.apple.root.default-qos
0 libsystem_kernel.dylib 0x19b556388 __pthread_kill + 8
1 libsystem_pthread.dylib 0x19b58f88c pthread_kill + 296
2 libsystem_c.dylib 0x19b498a3c abort + 124
3 libc++abi.dylib 0x19b545384 abort_message + 132
4 libc++abi.dylib 0x19b533cf4 demangling_terminate_handler() + 344
5 libobjc.A.dylib 0x19b1b8dd4 _objc_terminate() + 156
6 libc++abi.dylib 0x19b544698 std::__terminate(void (*)()) + 16
7 libc++abi.dylib 0x19b547c30 __cxxabiv1::failed_throw(__cxxabiv1::__cxa_exception*) + 88
8 libc++abi.dylib 0x19b547bd8 __cxa_throw + 92
9 libobjc.A.dylib 0x19b1aecf8 objc_exception_throw + 448
10 Foundation 0x19d5c3840 -[NSXPCConnection setCodeSigningRequirement:] + 140
11 libxpcfileprovider.dylib 0x301023048 NSXPCConnection.setCodeSigningRequirementFromTeamIdentifier(_:) + 1796
12 libxpcfileprovider.dylib 0x30101dc94 closure #1 in CallbackFileProviderManager.getFileProviderConnection(_:service:completionHandler:interruptionHandler:exportedObject:) + 1936
13 libxpcfileprovider.dylib 0x30101e110 thunk for @escaping @callee_guaranteed @Sendable (@guaranteed NSXPCConnection?, @guaranteed Error?) -> () + 80
14 Foundation 0x19d46c3a4 __72-[NSFileProviderService getFileProviderConnectionWithCompletionHandler:]_block_invoke_2.687 + 284
15 libdispatch.dylib 0x19b3d7b2c _dispatch_call_block_and_release + 32
16 libdispatch.dylib 0x19b3f185c _dispatch_client_callout + 16
17 libdispatch.dylib 0x19b40e490 + 32
18 libdispatch.dylib 0x19b3e9fa4 _dispatch_root_queue_drain + 736
19 libdispatch.dylib 0x19b3ea5d4 _dispatch_worker_thread2 + 156
20 libsystem_pthread.dylib 0x19b58be28 _pthread_wqthread + 232
21 libsystem_pthread.dylib 0x19b58ab74 start_wqthread + 8
The designated codesign requirement on the XPC connection is set to
anchor apple generic and certificate leaf[subject.OU] = <DEVELOPER_ID_TEAM_IDENTIFIER>"
We have verified the designated code sign requirement to be valid on both the main bundle and the embedded extension using:
codesign --verify -v -R '=anchor apple generic and certificate leaf[subject.OU] = "<DEVELOPER_ID_TEAM_IDENTIFIER>"' *.app
codesign --verify -v -R '=anchor apple generic and certificate leaf[subject.OU] = "<DEVELOPER_ID_TEAM_IDENTIFIER>"' *.app/Contents/PlugIns/*
In macOS 26 I noticed there is a section Menu Bar in System Settings which allows to toggle visibility of status items created with NSStatusItem. I'm assuming this is new, since I never noticed it before.
Currently my app has a menu item that allows toggling its status item, but now I wonder whether it should always create the status item and let the user control its visibility from System Settings. Theoretically, keeping this option inside the app could lead to confusion if the user has previously disabled the status item in System Settings, then perhaps forgot about it, and then tries to enable it inside the app, but apparently nothing happens because System Settings overrides the app setting. Should I remove the option inside the app?
This also makes me think of login items, which can be managed both in System Settings and inside the app via SMAppService. Some users ask why my app doesn't have a launch at login option, and I tell them that System Settings already offers that functionality. Since there is SMAppService I could offer an option inside the app that is kept in sync with System Settings, but I prefer to avoid duplicating functionality, particularly if it's something that is changed once by the user and then rarely (if ever) changed afterwards. But I wonder: why can login items be controlled by an app, and the status item cannot (at least I'm not aware of an API that allows to change the option in System Settings)? If the status item can be overridden in System Settings, why do login items behave differently?
In iOS Background Execution limits, I see this:
When the user ‘force quits’ an app by swiping up in the multitasking UI, iOS interprets that to mean that the user doesn’t want the app running at all. iOS also sets a flag that prevents the app from being launched in the background. That flag gets cleared when the user next launches the app manually.
However, I see that when I close an app on iPadOS 26 with the red X, the app doesn't appear in the multitasking UI. So are they treated as force closes and prevented from running background tasks?
I'm trying to understand how the API works to perform a function that can continue running if the user closes the app. For a very simple example, consider a function that increments a number on screen every second, counting from 1 to 100, reaching completion at 100. The user can stay in the app for 100s watching it work to completion, or the user can close the app say after 2s and do other things while watching it work to completion in the Live Activity.
To do this when the user taps a Start Counting button, you'd
1 Call BGTaskScheduler.shared.register(forTaskWithIdentifier:using:launchHandler:).
Question 1: Do I understand correctly, all of the logic to perform this counting operation would exist entirely in the launchHandler block (noting you could call another function you define passing it the task to be able to update its progress)? I am confused because the documentation states "The system runs the block of code for the launch handler when it launches the app in the background." but the app is already open in the foreground. This made me think this block is not going to be invoked until the user closes the app to inform you it's okay to continue processing in the background, but how would you know where to pick up. I want to confirm my thinking was wrong, that all the logic should be in this block from start to completion of the operation, and it's fine even if the app stays in the foreground the whole time.
2 Then you'd create a BGContinuedProcessingTaskRequest and set request.strategy = .fail for this example because you need it to start immediately per the user's explicit tap on the Start Counting button.
3 Call BGTaskScheduler.shared.submit(request).
Question 2: If the submit function throws an error, should you handle it by just performing the counting operation logic (call your function without passing a task)? I understand this can happen if for some reason the system couldn't immediately run it, like if there's already too many pending task requests. Seems you should not show an error message to the user, should still perform the request and just not support background continued processing for it (and perhaps consider showing a light warning "this operation can't be continued in the background so keep the app open"). Or should you still queue it up even though the user wants to start counting now? That leads to my next question
Question 3: In what scenario would you not want the operation to start immediately (the queue behavior which is the default), given the app is already in the foreground and the user requested some operation? I'm struggling to think of an example, like a button titled Compress Photos Whenever You Can, and it may start immediately or maybe it won't? While waiting for the launchHandler to be invoked, should the UI just show 0% progress or "Pending" until the system can get to this task in the queue? Struggling to understand the use cases here, why make the user wait to start processing when they might not even intend to close the app during the operation?
Thanks for any insights! As an aside, a sample project with a couple use cases would have been incredibly helpful to understand how the API is expected to be used.
Hello,
I have a few questions regarding the documentation here:
Can this method described in the article be built with Xcode 26 and run on iOS 26? Or is it restricted to run only on iOS 26, since AppExtensionPoint appears to be available starting from iOS 26?
Does this approach allow two apps under the same Team ID to communicate with each other?
Does this approach also allow two apps under different Team IDs to communicate with each other?
Is it mandatory to implement EXAppExtensionBrowserViewController and obtain user consent before using this method to exchange information?
In our implementation, we followed the documentation. Inside EXAppExtensionBrowserViewController, we were able to see the Generic Extension from another app and enabled the permission.
However, we still get the following error:
Failed to connect: Error Domain=NABUExtensionConnector Code=1
"No matching extension found"
UserInfo={NSLocalizedDescription=No matching extension found}
Could someone clarify whether this is expected behavior, or if we are missing an additional configuration step?
Thanks in advance!
Hello,
In a launched agent, I need to call into a third‑party library that may occasionally hang. At present, these calls are made from a separate thread, but if the thread hangs it cannot be terminated (pthread_cancel/pthread_kill are ineffective).
Would Apple recommend isolating this functionality in a separate process that can be force‑terminated if it becomes unresponsive, or is there a preferred approach for handling such cases in launched agents?
Can I use the system call fork() in launched agent?
Thank you in advance!
Hi, I have been recently debugging the BGContinuedProcessingTask API and encountered some of the following issues. I hope you can provide some answers:
First, let me explain my understanding of this API. I believe its purpose is to allow an app to trigger tasks that can be represented with progress indicators and require a certain amount of time to complete.
After entering the background, these tasks can continue to be completed through the BGContinuedProcessingTask, preventing the system from terminating them before they are finished.
In the launchHandler of the registration process, we only need to do a few things:
Determine whether the actual business processing is still ongoing.
Update the progress, title, and subtitle.
Handle the expirationHandler.
Set the task as completed.
Here are some issues I encountered during my debugging process:
After I called register and submit, the BGContinuedProcessingTask could not be triggered. The return values from my API calls were all normal.
I tried different device models, and some could trigger the task normally, such as the 15 Pro Max and 12 Pro Max. However, there were also some models, such as the 17 Pro, 15 Pro, and 15, that could not trigger the task properly. Moreover, there was no additional error information to help locate the issue.
The background task failed unexpectedly, but my app was still running normally. As I mentioned above, my launchHandler only retrieves the actual business status and updates it.
If a background task fails unexpectedly while the app is still running normally, it can mislead users and degrade the user experience of the app.
Others have also mentioned the issue of inconsistent behavior on devices that do not support Dynamic Island. On devices that support Dynamic Island,
when a task is triggered in the foreground, the app does not immediately display a pop-up notification within the app. However, on devices that do not support Dynamic Island,
the app directly displays a pop-up notification within the app, and this notification does not disappear when switching between different screens within the same app.
The user needs to actively swipe up to dismiss it. I think this experience is too intrusive for users. I would like to know whether this will be maintained in the future or if there is a plan to fix it.
On devices that do not support Dynamic Island, using the beta version 26.1 of the system,
if the system is in dark mode but the app triggers a business interface in white, the pop-up notification will have the same color as the current page, making it difficult to read the content inside the pop-up.
Users can actively stop background tasks by using the stop button, or the system can also stop tasks automatically when resources are insufficient or when a task is abnormal.
However, according to the current API, all these actions are triggered through the expirationHandler.
Currently, there is no way to distinguish whether the task was stopped by the user, by the system due to resource insufficiency, or due to an abnormal task.
I would like to know whether there will be more information provided in the future to help distinguish these different scenarios.
I believe that the user experience issues mentioned in points 2 and 3 are the most important. Please help to answer the questions and concerns above. Thank you!
i am trying to create a daemon with xpc for my app by referring to https://github.com/alienator88/HelperToolApp but i keep getting XPC remote proxy error: Couldn’t communicate with a helper application. All the identifiers all correct but the helper code is not reached.
On macOS 15.7.1 I'm trying to install an XPC service outside the app (Developer ID). It mostly seems to go ok, but when I set Launch Constraints on Responsible, AMFI complains of a violation, saying the service is responsible for itself, and fails to launch. Removing that constraint (or adding the service itself to the constraint) works fine.
The service is an optional download, and installed to /Users/Shared with a LaunchAgent specifying the MachService. The service is correctly launched and seems to pass all codesigning, notarization, and other checks, but the Responsible isn't set to the "calling" app.
Is this broken, or working as intended?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
XPC
Code Signing
Developer ID
Service Management
Issue:
Background downloads using the flutter_downloader package work perfectly in debug mode and release mode when run directly from Xcode (plugged in).
However, when I create an archive build and install the app separately (via TestFlight or direct IPA install), the background download stops working as soon as the app is minimized.
✅ What I’ve already done
Info.plist
<key>UIBackgroundModes</key>
<array>
<string>remote-notification</string>
<string>fetch</string>
<string>processing</string>
<string>audio</string>
<string>push-to-talk</string>
</array>
AppDelegate.swift
import UIKit
import Flutter
import Firebase
import flutter_downloader
import BackgroundTasks
@main
@objc class AppDelegate: FlutterAppDelegate {
static let backgroundChannel = "com.example.app/background_service"
private var backgroundCompletionHandler: (() -> Void)?
override func application(
_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
) -> Bool {
FirebaseApp.configure()
GeneratedPluginRegistrant.register(with: self)
FlutterDownloaderPlugin.setPluginRegistrantCallback(registerPlugins)
if #available(iOS 10.0, *) {
UNUserNotificationCenter.current().delegate = self
}
if #available(iOS 13.0, *) {
registerBackgroundTask()
}
return super.application(application, didFinishLaunchingWithOptions: launchOptions)
}
@available(iOS 13.0, *)
private func registerBackgroundTask() {
BGTaskScheduler.shared.register(
forTaskWithIdentifier: "com.example.app.process_download_queue",
using: nil
) { [weak self] task in
guard let self = self else { return }
self.handleDownloadQueueTask(task: task as! BGProcessingTask)
}
}
@available(iOS 13.0, *)
private func handleDownloadQueueTask(task: BGProcessingTask) {
scheduleNextDownloadTask()
let headlessEngine = FlutterEngine(name: "BackgroundTaskEngine", project: nil, allowHeadlessExecution: true)
headlessEngine.run()
let channel = FlutterMethodChannel(
name: AppDelegate.backgroundChannel,
binaryMessenger: headlessEngine.binaryMessenger
)
task.expirationHandler = {
channel.invokeMethod("backgroundTaskExpired", arguments: nil)
}
channel.invokeMethod("processNextInBackground", arguments: nil) { result in
task.setTaskCompleted(success: (result as? Bool) ?? false)
}
}
override func application(
_ application: UIApplication,
handleEventsForBackgroundURLSession identifier: String,
completionHandler: @escaping () -> Void
) {
self.backgroundCompletionHandler = completionHandler
super.application(application, handleEventsForBackgroundURLSession: identifier, completionHandler: completionHandler)
}
override func applicationDidEnterBackground(_ application: UIApplication) {
if #available(iOS 13.0, *) {
scheduleNextDownloadTask()
}
}
@available(iOS 10.0, *)
override func userNotificationCenter(
_ center: UNUserNotificationCenter,
willPresent notification: UNNotification,
withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void
) {
if #available(iOS 14.0, *) {
completionHandler([.list, .banner, .badge, .sound])
} else {
completionHandler([.alert, .badge, .sound])
}
}
@available(iOS 10.0, *)
override func userNotificationCenter(
_ center: UNUserNotificationCenter,
didReceive response: UNNotificationResponse,
withCompletionHandler completionHandler: @escaping () -> Void
) {
completionHandler()
}
}
// MARK: - Helper
@available(iOS 13.0, *)
func scheduleNextDownloadTask() {
let request = BGProcessingTaskRequest(identifier: "com.example.app.process_download_queue")
request.requiresNetworkConnectivity = true
request.requiresExternalPower = false
request.earliestBeginDate = Date(timeIntervalSinceNow: 60)
do {
try BGTaskScheduler.shared.submit(request)
print("BGTask: Download queue processing task scheduled successfully.")
} catch {
print("BGTask: Could not schedule download queue task: \(error)")
}
}
private func registerPlugins(registry: FlutterPluginRegistry) {
if !registry.hasPlugin("FlutterDownloaderPlugin") {
FlutterDownloaderPlugin.register(with: registry.registrar(forPlugin: "FlutterDownloaderPlugin")!)
}
}
🧩 Observations
Background download works correctly when:
The app is plugged in and run via Xcode (release/debug)
It stops working when:
The app is installed from an archived build (IPA/TestFlight) and minimized
All entitlements and background modes are properly added.
Provisioning profile includes required background modes.
❓Question
Is there any known limitation or signing difference between Xcode run and archived release builds that could cause URLSession background tasks not to trigger?
Has anyone faced a similar issue when using flutter_downloader on iOS 13+ with BGTaskScheduler or URLSession background configuration?
Any help or working setup example for production/TestFlight would be appreciated.
For example, let’s propose an XPC service that can connect to websites. Suppose that I want to connect to Apple.com, microsoft.com, and ibm.com. Can 3 service objects be made between the service and client? Or does the service have to return an ID for each web connection, with the client needing to specify which connection ID along with a command?
Just trying to understand the documentation.
Obviously, we can send a request to the service to return all the data at once. Can the data arrive in pieces, involving either multiple async callbacks or a Combine Publisher?
iOS BGProcessingTask + Background Upload Not Executing Reliably on TestFlight (Works in Debug)
Description:
We are facing an issue with BGTaskScheduler and BGProcessingTask when trying to perform a background audio-upload flow on iOS. The behavior is inconsistent between Debug builds and TestFlight (Release) builds.
Summary of the Problem
Our application records long audio files (up to 1 hour) and triggers a background upload using:
BGTaskScheduler
BGProcessingTaskRequest
Background URLSession (background with identifier)
URLSession background upload task + AppDelegate.handleEventsForBackgroundURLSession
In Debug mode (Xcode → Run on device), everything works as expected:
BGProcessingTask executes
handleEventsForBackgroundURLSession fires
Background URLSession continues uploads reliably
Long audio files successfully upload even when the app is in background or terminated
However, in TestFlight / Release mode, the system does not reliably launch the BGProcessingTask or Background URLSession events.
Technical Details
We explicitly register BGTaskScheduler:
BGTaskScheduler.shared.register(
forTaskWithIdentifier: "example.background.process",
using: nil
) { task in
self.handleBackgroundProcessing(task: task as! BGProcessingTask)
}
We schedule it using:
let request = BGProcessingTaskRequest(identifier: "example.background.process")
request.requiresNetworkConnectivity = true
request.requiresExternalPower = false
try BGTaskScheduler.shared.submit(request)
We also use Background URLSession:
let config = URLSessionConfiguration.background(withIdentifier: sessionId)
config.sessionSendsLaunchEvents = true
config.isDiscretionary = false
AppDelegate.handleEventsForBackgroundURLSession is implemented correctly and works in Debug.
Issue Observed (TestFlight Only)
In TestFlight builds:
BGProcessingTask rarely triggers, or the system marks it as NO LONGER RUNNING.
Background upload tasks sometimes never start or complete.
No logs appear from our BGProcessingTask handler.
system logs show messages like:
NO LONGER RUNNING bgProcessing-example.background.process
Tasks running in group [com.apple.dasd.defaultNetwork] are 1!
This occurs most frequently for large audio uploads (30–60 minutes), while small files behave normally.
What We Have Verified
Proper Info.plist values:
Permitted background modes: processing, audio, fetch
BGTaskSchedulerPermittedIdentifiers contains our identifier
BGProcessingTask is being submitted successfully (no errors)
App has microphone permission + background audio works
Device plugged/unplugged doesn’t change outcome
Key Question for Apple
We need clarification on:
Why BGProcessingTask behave differently between Debug and TestFlight builds?
Are there additional restrictions or heuristics (related to file size, CPU usage, runtime, network load, or power constraints) that cause BGProcessingTask to be throttled or skipped in Release/TestFlight?
How can we guarantee a background upload continues reliably for large files (100MB–500MB) on TestFlight and App Store builds?
Is there an Apple-recommended pattern to combine BGProcessingTask + Background URLSession for long-running uploads?
Expected Result
Background uploads should continue reliably for long audio files (>30 minutes) when the app goes to background or is terminated, in the same way they currently function in Debug builds.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
iOS
Background Tasks
Foundation
CFNetwork
Regarding the Background Assets capability on iOS:
In the install scenario, resources defined as the "install" type are incorporated into the App Store download progress. Do resources of the "update" type in the update scenario also get incorporated into the App Store download progress in the same way?
If an exception occurs during the download of install-type resources and the download cannot proceed further, will the system no longer actively block users from launching the app and instead enable the launch button?
Currently, if a user has enabled automatic updates on their device, after the app is updated and released on the App Store, will the Background Assets download start immediately once the automatic update completes? Or does Background Assets have its own built-in scheduling logic that prevents it from running concurrently with the automatic update?
I posted here https://developer.apple.com/forums/thread/805554?page=1#867766022 but posting again for visibility (and let me know how I can file a bug)
There was a response in that thread that said you could use the childProgress system to help updating progresses to keep the backgroundTask alive.
What I've found is that using childProgresses results in more terminations than if you just updated the progress directly.
Here is my setups to test this
A BGContinuedProcessingTask that uses URLSessions to upload, and registers the task.progress with the Urlsession Progress
Same, but the task.progress gets updated via a UrlSession Callback
The second is MUCH more stable out in the field in cellular settings, the first fails extremely frequently.
My suspicion is that in the documentation here https://developer.apple.com/documentation/foundation/progress#Reporting-Progress-for-Multiple-Operations
it explicitly states
The completedUnitCount property for a containing progress object only updates when the suboperation is 100% complete. The fractionCompleted property for a containing progress object updates continuously as work progresses for all suboperations.
I wonder if BGContinuedProcessingTask is only looking at completedUnitCount for progress, and not fractionCompleted?
In either case, I would love to use the childProgresses because there are bugs with retries by updating the progress manually, so would love some help resolving this, Thanks!
I've tuned my task to be decently resilient, but I found a few issues that caused it to expire regularly.
excessive CPU usage -> I'm actually running it behind ReactNative, and I found an issue where I was still updating ReactNative and thus it was keeping it alive the entire time the task was running. Removing this update helped improve stability
not updating progress frequently enough ( see https://developer.apple.com/forums/thread/809182?page=1#868247022)
My feature request is, would it be possible to get a reason the task was expired in task.expirationHandler? That would be helpful for both the user and for debugging why the task was expired. Thanks!
We are seeing a strange lifecycle issue on multiple MDM-managed iPads where
application(_:didFinishLaunchingWithOptions:) is not called after the device is idle overnight.
Even if we terminate the app manually via the app switcher, the next morning the system does not perform a cold launch. Instead, the app resumes directly in:
applicationDidBecomeActive(_:)
This causes all initialization logic that depends on didFinishLaunching to be completely skipped.
This behavior is consistent across four different supervised MDM devices.
Environment
Devices: iPads enrolled in MDM (supervised)
iOS version: 18.3
Xcode: 16.4
macOS: Sequoia 15.7.2
App type: Standard UIKit iOS app
App: Salux Audiometer (App Store app)
Expected Behavior
If the app was terminated manually using the app switcher, the next launch should:
Start a new process
Trigger application(_:didFinishLaunchingWithOptions:)
Follow the normal cold-start lifecycle
Actual Behavior
After leaving the iPad idle overnight (8–12 hours):
The next launch skips didFinishLaunching
The app resumes directly in applicationDidBecomeActive
No new process is started
App behaves as if it had been suspended, even though it was manually terminated
Logs (Relevant Extracts)
Day 1 — Normal cold launch
[12:06:44.152 PM] PROCESS_STARTED
[12:06:44.214 PM] DID_FINISH_LAUNCHING_START launchOptions=[]
[12:06:44.448 PM] DID_FINISH_LAUNCHING_END
We then used the app and terminated it via app switcher.
Day 2 — Unexpected resume without cold start
[12:57:49.328 PM] APP_DID_BECOME_ACTIVE
No PROCESS_STARTED
No didFinishLaunching
No cold-start logs
This means the OS resumed the app from a previous state that should not exist.
Reproducible Steps
Use an MDM-enrolled iPad.
Launch the app normally.
Terminate it manually via the multitasking app switcher.
Leave the device idle overnight (8–12 hours).
Launch the app the next morning.
Observe that:
didFinishLaunching does not fire
applicationDidBecomeActive fires directly
Questions for Apple Engineers / Community
Is this expected behavior on MDM-supervised devices in iOS 18?
Are there any known OS-level changes where terminated apps may be revived from disk/memory?
Could MDM restrictions or background restoration policies override app termination?
How can we ensure that our app always performs a clean initialization when launched after a long idle period?
Additional Information
We have full logs from four separate MDM iPads showing identical behavior.
Happy to share a minimal reproducible sample if required.
Regarding App Update Synchronization During Workout Mode:
My watchOS app has workout mode enabled. When I update the app from the App Store on my iPhone while a workout session is active on my Apple Watch, the update does not sync to the watch. Why does this happen, and when can I expect the watch app to be updated?
Regarding Automatic App Launch After a Prolonged Shutdown:
I would like my watchOS app to launch automatically on my Apple Watch after it has been powered off for an extended period and then turned back on. Is this functionality possible to implement? If not, please provide a definitive answer regarding this capability.
I have an older project that was created before Xcode 26.2.
In Xcode versions prior to 26.2, there was no Swift Compiler – Concurrency build setting.
With those older versions, the following behavior occurs: a nonisolated function executes off the main thread.
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
run()
}
private func run() {
Task {
await runInMainThread()
}
}
func runInMainThread() async {
print(">>>> IN runInMainThread(), Thread.isMainThread \(Thread.isMainThread)")
await runInBackgroundThread()
}
private nonisolated func runInBackgroundThread() async {
print(">>>> IN runInBackgroundThread(), Thread.isMainThread \(Thread.isMainThread)")
}
}
Output:
>>>> IN runInMainThread(), Thread.isMainThread true
>>>> IN runInBackgroundThread(), Thread.isMainThread false
However, starting with Xcode 26.2, Apple introduced the Swift Compiler – Concurrency settings.
When running the same code with the default configuration:
Approachable Concurrency = Yes
Default Actor Isolation = MainActor
This is the output
Output:
>>>> IN runInMainThread(), Thread.isMainThread true
>>>> IN runInBackgroundThread(), Thread.isMainThread true
the nonisolated function now executes on the main thread.
This raises the following questions:
What is the correct Swift Compiler – Concurrency configuration if I want a nonisolated function to run off the main thread?
Is nonisolated still an appropriate way to ensure code runs on a background thread?