When I use BGContinuedProcessingTask to submit a task, my iPhone 12 immediately shows a notification banner displaying the task’s progress.
However, on my iPhone 15 Pro Max, there’s no response — the progress UI only appears in the Dynamic Island after I background the app.
Why is there a difference in behavior between these two devices?
Is it possible to control the UI so that the progress indicator only appears when the app moves to the background?
Processes & Concurrency
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Hello,
https://developer.apple.com/forums/thread/802443
https://developer.apple.com/documentation/servicemanagement/updating-helper-executables-from-earlier-versions-of-macos
https://developer.apple.com/documentation/ServiceManagement/updating-your-app-package-installer-to-use-the-new-service-management-api#Run-the-sample-launch-agent
Read these.
Earlier we had a setup with SMJobBless, now we have migrated to SMAppService.
Everything is working fine, the new API seems easier to manage, but we are having issues with updating the daemon.
I was wondering, what is the right process for updating a daemon from app side?
What we are doing so far:
App asks daemon for version
If version is lower than expected:
daemon.unregister(), wait a second and daemon.register() again.
The why?
We have noticed that unregistering/registering multiple times, of same daemon, can cause the daemon to stop working as expected. The daemon toggle in Mac Settings -> Login Items & Extensions can be on or off, but the app can still pickup daemon running, but no daemon running in Activity monitor. Registration/unregistration can start failing and nothing helps to resolve this, only reseting with sfltool resetbtm and a restart seems to does the job. This is usually noticeable for test users, testing same daemon version with different app builds.
In production app, we also increase the bundle version of daemon in plist, in test apps we - don't.
I haven't found any sources of how the update of pre-bundled app daemon should work.
Initial idea is register/unregister, but from what I have observed, this seems to mess up after multiple registrations.
I have a theory, that sending the daemon a command to kill itself after app update, would load the latest daemon.
Also, I haven't observed for daemon, with different build versions to update automatically.
What is the right way to update a daemon with SMAppService setup?
Thank you in advance.
Hi,
This post is coming from frustration of working on using BGContinuedProcessingTask for almost 2 weeks, trying to get it to actually complete in the background after the app is backgrounded.
My process will randomlly finish and not finish and have no idea why.
I'm properly using and setting
task?.progress.totalUnitCount = [some number]
task?.progress.completedUnitCount = [increment as processed]
I know this, because it all looks propler as long as the app insn't backgrounded. So it's not a progress issue. The task will ALWAYS complete.
The device has full power, as it is plugged in as I run from within Xcode. So, it's not a power issue.
Yes, the process will take a few minutes, but I thought that is BGContinuedProcessingTask purpose in iOS 26. For long running process that a user could place in the background and leave the app, assuming the process would actually finish.
Why bother introducing a feature that only works with short tasks that don't actually need long running time in the first place.
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!
TCC Permission Inheritance for Python Process Launched by Swift App in Enterprise Deployment
We are developing an enterprise monitoring application that requires a hybrid Swift + Python architecture due to strict JAMF deployment restrictions. We must deploy a macOS application via ABM/App Store Connect, but our core monitoring logic is in a Python daemon. We need to understand the feasibility and best practices for TCC permission inheritance in this specific setup.
Architecture
Component
Bundle ID
Role
Deployment
Swift Launcher
com.athena.AthenaSentry
Requests TCC permissions, launches Python child process.
Deployed via ABM/ASC.
Python Daemon
com.athena.AthenaSentry.Helper
Core monitoring logic using sensitive APIs.
Nested in Contents/Helpers/.
Both bundles are signed with the same Developer ID and share the same Team ID.
Required Permissions
The Python daemon needs to access the following sensitive TCC-controlled services:
Screen Recording (kTCCServiceScreenCapture) - for capturing screenshots.
Input Monitoring (kTCCServiceListenEvent) - for keystroke/mouse monitoring.
Accessibility (kTCCServiceAccessibility) - a prerequisite for Input Monitoring.
Attempts & Workarounds
We have attempted to resolve this using:
Entitlement Inheritance: Added com.apple.security.inherit to the Helper's entitlements.
Permission Proxy: Swift app maintains active event taps to try and "hold" the permissions for the child.
Foreground Flow: Keeping the Swift app in the foreground during permission requests.
Questions
Is this architecture supported? Can a Swift parent app successfully request TCC permissions that a child process can then use?
TCC Inheritance: What are the specific rules for TCC permission inheritance between parent/child processes in enterprise environment?
What's the correct approach for this enterprise use case? Should we:
Switch to a Single Swift App? (i.e., abandon the Python daemon and rewrite the core logic natively in Swift).
Use XPC Services? (instead of launching the child process directly).
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Enterprise
Entitlements
Privacy
Scripting
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.
I've adopted the new BGContinuedProcessingTask in iOS 26, and it has mostly been working well in internal testing. However, in production I'm getting reports of the tasks failing when the app is put into the background.
A bit of info on what I'm doing: I need to download a large amount of data (around 250 files) and process these files as they come down. The size of the files can vary: for some tasks each file might be around 10MB. For other tasks, the files might be 40MB. The processing is relatively lightweight, but the volume of data means the task can potentially take over an hour on slower internet connections (up to 10GB of data).
I set the totalUnitCount based on the number of files to be downloaded, and I increment completedUnitCount each time a file is completed.
After some experimentation, I've found that smaller tasks (e.g. 3GB, 10MB per file) seem to be okay, but larger tasks (e.g. 10GB, 40MB per file) seem to fail, usually just a few seconds after the task is backgrounded (and without even opening any other apps). I think I've even observed a case where the task expired while the app was foregrounded!
I'm trying to understand what the rules are with BGContinuedProcessingTask and I can see at least four possibilities that might be relevant:
Is it necessary to provide progress updates at some minimum rate? For my larger tasks, where each file is ~40MB, there might be 20 or 30 seconds between progress updates. Does this make it more likely that the task will be expired?
For larger tasks, the total time to complete can be 60–90 mins on slower internet connections. Is there some maximum amount of time the task can run for? Does the system attempt some kind of estimate of the overall time to complete and expire the task on that basis?
The processing on each file is relatively lightweight, so most of the time the async stream is awaiting the next file to come down. Does the OS monitor the intensity of workload and suspend the task if it appears to be idle?
I've noticed that the task UI sometimes displays a message, something along the lines of "Do you want to continue this task?" with a "Continue" and "Stop" option. What happens if the user simply ignores or doesn't see this message? Even if I tap "Continue" the task still seems to fail sometimes.
I've read the docs and watched the WWDC video, but there's not a whole lot of information on the specific issues I mention above. It would be great to get some clarity on this, and I'd also appreciate any advice on alternative ways I could approach my specific use case.
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
I would like to know whether BGContinuedProcessingTaskRequest supports executing asynchronous tasks internally, or if it can only execute synchronous tasks within BGContinuedProcessingTaskRequest?
Our project is very complex, and we now need to use BGContinuedProcessingTaskRequest to perform some long-running operations when the app enters the background (such as video encoding/decoding & export). However, our export interface is an asynchronous function, for example video.export(callback: FinishCallback). This export call returns immediately, and when the export completes internally, it calls back through the passed-in callback. So when I call BGTaskScheduler.shared.register to register a BGContinuedProcessingTask, what should be the correct approach? Should I directly call video.export(nil) without any waiting, or should I wait for the export function to complete in the callback?
For example:
BGTaskScheduler.shared.register(forTaskWithIdentifier: "com.xxx.xxx.xxx.xxx", using: nil) { task in
guard let continuedTask = task as? BGContinuedProcessingTask else {
task.setTaskCompleted(success: false)
return
}
let scanner = SmartAssetsManager.shared
let semaphore = DispatchSemaphore(value: 0)
continuedTask.expirationHandler = {
logError(items: "xwxdebug finished.")
semaphore.signal()
}
logInfo(items: "xwxdebug start!")
video.export { _ in
semaphore.signal()
}
semaphore.wait()
logError(items: "xwxdebug finished!")
}
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.
If I create a BGContinuedProcessingTaskRequest, register it, and then "do work" within it appropriately reporting progress, and before my task has finished doing all the work it had to do, its expirationHandler triggers...
does the task later try again?
Or does it lose the execution opportunity until the app is next re-launched to the foreground?
In my testing, I never saw my task execute again once expired (which suggests the latter?).
I was able to easily force this expiry by starting my task, backgrounding my app, then launching the iOS Camera App. My example is just using test code inspired from https://developer.apple.com/documentation/backgroundtasks/performing-long-running-tasks-on-ios-and-ipados
let request = BGContinuedProcessingTaskRequest(identifier: taskIdentifier, title: "Video Upload", subtitle: "Starting Upload")
request.strategy = .queue
BGTaskScheduler.shared.register(forTaskWithIdentifier: taskIdentifier, using: nil) { task in
guard let task = task as? BGContinuedProcessingTask else { return }
print("i am a good task")
var wasExpired = false
task.expirationHandler = {
wasExpired = true
}
let progress = task.progress
progress.totalUnitCount = 100
while !progress.isFinished && !wasExpired {
progress.completedUnitCount += 1
let formattedProgress = String(format: "%.2f", progress.fractionCompleted * 100)
task.updateTitle(task.title, subtitle: "Completed \(formattedProgress)%")
sleep(1)
}
if progress.isFinished {
print ("i was a good task")
task.setTaskCompleted(success: true)
} else {
print("i was not a good task")
task.setTaskCompleted(success: false)
}
}
try? BGTaskScheduler.shared.submit(request)
Apologies if this is clearly stated somewhere and I'm missing it.
Since macOS 26, including the latest 26.1, the menu bar icon does not show up for our app called Plover which is built with PySide6 (based on Qt 6) and runs via a relocatable python that is packaged into the app. The code is open source and can be found on GitHub. The latest release, including the notarized DMG, can be found here.
When running the .app via the command below, the menu bar icon does show up but the process that is running is python3.13 and not Plover:
/Applications/Plover.app/Contents/MacOS/Plover -l debug
When running the app by just clicking on the application icon, the process is Plover but the menu bar icon is not showing - also not in the settings (Menu Bar > Allow in the Menu Bar). Before macOS 26, the menu bar icon was always shown.
Some pointers to potentially relevant parts of our code:
shell script that builds the .app
Info.plist
plover_launcher.c
trayicon.py
This problem might be related to this thread, including the discussion around Qt not calling NSApplicationMain.
What I'm trying to figure out is whether this is a problem with macOS 26, Qt 6, PySide6, or our code.
Any pointers are highly appreciated!
Topic:
App & System Services
SubTopic:
Processes & Concurrency
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?
I have an app for macOS that is built using Mac Catalyst. I need to perform some background processing. I'm using BGProcessingTaskRequest to schedule the request. I have also integrated CKSyncEngine so I need that to be able to perform its normal background processing.
On iOS, when the user leaves the app, I can see a log message that the request was scheduled and a bit later I see log messages coming from the actual background task code.
On macOS I ran the app from Xcode. I then quit the app (Cmd-q). I can see the log message that the request was scheduled. But the actual task is never run. In my test, I ran my app on a MacBook Pro running macOS 26.0. When I quit the app, I checked the log file in the app sandbox and saw the message that the task was scheduled. About 20 minutes later I closed the lid on the MacBook Pro for the night. I did not power down, it just went to sleep. Roughly 10 hours later I opened the lid on the MacBook Pro, logged in, and checked the log file. It had not been updated since quitting the app. I should also mention that the laptop was not plugged in at all during this period.
My question is, does a Mac Catalyst app support background processing after the user quits the app? If so, how is it enabled?
The documentation for BGProcessingTaskRequest and BGProcessingTask show they are supported under Mac Catalyst, but I couldn't find any documentation in the Background Tasks section that mentioned anything specific to setup for Mac Catalyst.
Running the Settings app and going to General -> Login Items & Extension, I do not see my app under the App Background Activity section. Does it need to be listed there? If so, what steps are needed to get it there?
If this is all documented somewhere, I'd appreciate a link since I was not able to find anything specific to making this work under Mac Catalyst.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
CloudKit
macOS
Mac Catalyst
Background Tasks
I implemented BGContinuedProcessingTask in my app and it seems to be working well for everyone except one user (so far) who has reached out to report nothing happens when they tap the Start Processing button. They have an iPhone 12 Pro Max running iOS 26.1. Restarting iPhone does not fix it.
When they turn off the background processing feature in the app, it works. In that case my code directly calls the function to start processing instead of waiting for it to be invoked in the register block (or submit catch block).
Is this a bug that's possible to occur, maybe device specific? Or have I done something wrong in the implementation?
func startProcessingTapped(_ sender: UIButton) {
if isBackgroundProcessingEnabled {
startBackgroundContinuedProcessing()
} else {
startProcessing(backgroundTask: nil)
}
}
func startBackgroundContinuedProcessing() {
BGTaskScheduler.shared.register(forTaskWithIdentifier: taskIdentifier, using: .main) { @Sendable [weak self] task in
guard self != nil else { return }
startProcessing(backgroundTask: task as? BGContinuedProcessingTask)
}
let request = BGContinuedProcessingTaskRequest(identifier: taskIdentifier, title: title, subtitle: subtitle)
request.strategy = .fail
if BGTaskScheduler.supportedResources.contains(.gpu) {
request.requiredResources = .gpu
}
do {
try BGTaskScheduler.shared.submit(request)
} catch {
startProcessing(backgroundTask: nil)
}
}
func startProcessing(backgroundTask: BGContinuedProcessingTask?) {
// FIXME: Never called for this user when isBackgroundProcessingEnabled is true
}
I'm specifically focused on Live Activity, but I think this is somewhat a general question. The app could get a few callbacks when:
There's a new payload (start, update, end)
There's a new token (start, update)
There's some other lifecycle event (stale, dismissed)
Assuming that the user didn't force kill the app, would the app get launched in all these scenarios?
When OS launches the app for a reason, should we wrap our tasks with beginBackgroundTask or that's unnecessary if we're expecting our tasks to finish within 30 seconds? Or the OS may sometimes be under stress and give you far less time (example 3 seconds) and if you're in slow internet, then adding beginBackgroundTask may actually come in handy?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
APNS
Background Tasks
ActivityKit
In the header for workloop.h there is this note:
A dispatch workloop is a "subclass" of dispatch_queue_t which can be passed to all APIs accepting a dispatch queue, except for functions from the dispatch_sync() family. dispatch_async_and_wait() must be used for workloop objects. Functions from the dispatch_sync() family on queues targeting a workloop are still permitted but discouraged for performance reasons.
I have a couple questions related to this. First, I'd like to better understand what the alluded-to 'performance reasons' are that cause this pattern to be discouraged in the 'queues targeting a workloop' scenario. From further interrogation of the headers, I've found these explicit callouts regarding differences in the dispatch_sync and dispatch_async_and_wait API:
dispatch_sync:
Work items submitted to a queue with dispatch_sync() do not observe certain queue attributes of that queue when invoked (such as autorelease frequency and QOS class).
dispatch_async_and_wait:
Work items submitted to a queue with dispatch_async_and_wait() observe all queue attributes of that queue when invoked (inluding [sic] autorelease frequency or QOS class).
Additionally, dispatch_async_and_wait has a section of the headers devoted to 'Differences with dispatch_sync()', though I can't say I entirely follow the distinctions it attempts to draw.
Based on that, my best guess is that the 'performance reasons' are something about either QoS not being properly respected/observed or some thread context switching differences that can degrade performance, but I would appreciate insight from someone with more domain knowledge.
My second question is a bit more general – taking a step back, why exactly do these two API exist? It's not clear to me from the existing documentation I've found why I would/should prefer dispatch_sync over dispatch_async_and_wait (other than the aforementioned callout noting the former is unsupported on workloops). What is the motivation for preserving both these API vs deprecating dispatch_sync in favor of dispatch_async_and_wait (or functionally subsuming one with the other)?
Credit to Luna for originally posing/inspiring these questions.
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