General:
Forums subtopic: App & System Services > Processes & Concurrency
Forums tag: Background Tasks
Background Tasks framework documentation
UIApplication background tasks documentation
ProcessInfo expiring activity documentation
Using background tasks documentation for watchOS
Performing long-running tasks on iOS and iPadOS documentation
WWDC 2020 Session 10063 Background execution demystified — This is critical resource. Watch it! [1]
WWDC 2022 Session 10142 Efficiency awaits: Background tasks in SwiftUI
iOS Background Execution Limits forums post
UIApplication Background Task Notes forums post
Testing and Debugging Code Running in the Background forums post
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
[1] Sadly the video is currently not available from Apple. I’ve left the link in place just in case it comes back.
Background Tasks
RSS for tagRequest the system to launch your app in the background to run tasks using Background Tasks.
Posts under Background Tasks tag
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My Mac app has a launch agent (within the app bundle) that works great without the app running. There are some occasions where I need to display an alert and ask the user to launch the app to handle the issue. I thought about using UNUserNotificationCenter but I'm not able to make it work from the agent.
I'm asking for authorization as follows:
[center requestAuthorizationWithOptions:(UNAuthorizationOptionAlert | UNAuthorizationOptionSound | UNAuthorizationOptionBadge)
completionHandler:^(BOOL granted, NSError * _Nullable error) {
NSLog(@"authorization request completion. Granted: %@, error: %@ (%@)",granted?@"YES":@"NO",error, [error localizedDescription]);
}];
And I'm trying to post the notification as follows:
content.title = @"Your App Name";
content.body = @"Click the button to open the app";
content.sound = [UNNotificationSound defaultSound];
UNNotificationRequest *request = [UNNotificationRequest requestWithIdentifier:[[NSUUID UUID] UUIDString]
content:content
trigger:nil];
[center addNotificationRequest:request withCompletionHandler:^(NSError * _Nullable error) {
if (error) {
NSLog(@"Error showing notification: %@ %@", error, [error localizedDescription]);
}
}];
When running I'm getting asked to authorize, I authorize and all seems OK in system settings but I'm not able send any notifications. addNotificationRequest results in UNErrorCodeNotificationsNotAllowed error.
I tried this with the authorization request inside the main app, or inside the agent, with the same results.
When trying to post the notification from within the app, it does work, but that's not what I need.
Is posting notifications from within the launch agent not possible at all, or is there anything here that I'm missing.
TIA
Topic:
App & System Services
SubTopic:
Notifications
Tags:
Extensions
User Notifications
Background Tasks
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?
I am currently developing a macOS app that can show system HUDs in the Notch
Till Sequoia I used to kill the OSDUIHelper process (which displays the default macOS Volume and Brightness control HUDs) - and replaced it with my app's HUDs
But, it is not working on macOS Tahoe anymore as the OSDUIHelper process is no longer there due to the UI changes
Has the process been renamed - or is there any other way to kill the process?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Swift
macOS
SwiftUI
Background Tasks
We're seeing a high velocity crash with our users in background tasks in an internal Apple Framework. It seems to have started in iOS 17/18, but has increased heavily in iOS 26+.
EXC_BREAKPOINT ·
0
BackBoardServices
-[BKSHIDEventDeliveryManager _initWithConnectionFactory:forTesting:]
1
BackBoardServices
___44+[BKSHIDEventDeliveryManager sharedInstance]_block_invoke
2
libdispatch.dylib
__dispatch_client_callout
3
libdispatch.dylib
__dispatch_once_callout
4
BackBoardServices
+[BKSHIDEventDeliveryManager sharedInstance]
5
UIKitCore
_stateMachineSpec_block_invoke_3
6
UIKitCore
_handleEvent
7
UIKitCore
-[_UIEventDeferringManager _processEventDeferringActions:actionsCount:inScope:forDeferringToken:environments:target:addingRecreationReason:removingRecreationReason:forReason:]
8
UIKitCore
-[_UIEventDeferringManager _sceneWillInvalidate:]
9
UIKitCore
-[UIScene _invalidate]
10
UIKitCore
-[UIWindowScene _invalidate]
11
UIKitCore
-[UIApplication workspace:willDestroyScene:withTransitionContext:completion:]
12
UIKitCore
-[UIApplicationSceneClientAgent scene:willInvalidateWithEvent:completion:]
13
FrontBoardServices
-[FBSScene _callOutQueue_willDestroyWithTransitionContext:completion:]
14
FrontBoardServices
___84-[FBSWorkspaceScenesClient _queue_invalidateScene:withTransitionContext:completion:]_block_invoke_3
15
FrontBoardServices
-[FBSWorkspace _calloutQueue_executeCalloutFromSource:withBlock:]
16
libdispatch.dylib
__dispatch_client_callout
17
libdispatch.dylib
__dispatch_block_invoke_direct
18
BoardServices
___BSSERVICEMAINRUNLOOPQUEUE_IS_CALLING_OUT_TO_A_BLOCK__
19
BoardServices
_BSServiceMainRunLoopSourceHandler
20
CoreFoundation
___CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__
21
CoreFoundation
___CFRunLoopDoSource0
22
CoreFoundation
___CFRunLoopDoSources0
23
CoreFoundation
___CFRunLoopRun
24
CoreFoundation
__CFRunLoopRunSpecificWithOptions
25
GraphicsServices
_GSEventRunModal
26
UIKitCore
-[UIApplication _run]
27
UIKitCore
_UIApplicationMain
28
Aura
main.m
main
29
dyld
start
Hi All,
I'm working on an app that needs to connect to BLE device and on defined schedules download data from the device. the amount of data is segnificant and might take around a minute to download. we tought about utilizing both state restoration and preservation for app waking and scheduling (triggered by the ble peripheral) and BGTaskScheduler to schedule a task that will handle a long running task to manage the full data download. now, will this solution in general valid? isnt it a "hack" that goes around the 10s limit that state restoration enforces?
i know there are limitations for BGTask (like when it runs, it might be terminated by the system etc) but considering that, can we proceed with this approach without breaching apple guidelines?
thank you in advance!
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Background Tasks
Core Bluetooth
Hi, I have a couple questions about background app refresh. First, is the function RefreshAppContentsOperation() where to implement code that needs to be run in the background? Second, despite importing BackgroundTasks, I am getting the error "cannot find operationQueue in scope". What can I do to resolve that? Thank you.
func scheduleAppRefresh() {
let request = BGAppRefreshTaskRequest(identifier: "peaceofmindmentalhealth.RoutineRefresh")
// Fetch no earlier than 15 minutes from now.
request.earliestBeginDate = Date(timeIntervalSinceNow: 15 * 60)
do {
try BGTaskScheduler.shared.submit(request)
} catch {
print("Could not schedule app refresh: \(error)")
}
}
func handleAppRefresh(task: BGAppRefreshTask) {
// Schedule a new refresh task.
scheduleAppRefresh()
// Create an operation that performs the main part of the background task.
let operation = RefreshAppContentsOperation()
// Provide the background task with an expiration handler that cancels the operation.
task.expirationHandler = {
operation.cancel()
}
// Inform the system that the background task is complete
// when the operation completes.
operation.completionBlock = {
task.setTaskCompleted(success: !operation.isCancelled)
}
// Start the operation.
operationQueue.addOperation(operation)
}
func RefreshAppContentsOperation() -> Operation {
}
Hello,
I have a question regarding the behavior of BGProcessingTaskRequest when the app is force-quit by the user via the App Switcher.
Based on common understanding and various discussions — including the following Apple Developer Forum threads:
Waking up an iOS app after app is … | Apple Developer Forums
Will BGAppRefreshTaskRequest will … | Apple Developer Forums
Background fetch after app is forc… | Apple Developer Forums
…it is widely understood that iOS prevents background execution (such as background fetch, push notifications, or BGTaskScheduler) after a user force-quits an app via the App Switcher.
However, in my app, I have observed that a scheduled BGProcessingTaskRequest still executes even after the app has been explicitly terminated via App Switcher. The task is scheduled using submit(_:error:), and it is clearly running some time after the app has been closed by the user.
That said, the task does run, but it appears to operate under tighter constraints — for example, it may be allowed to run for a shorter duration, and network requests appear to be more restricted compared to when the app is not force-quit.
My questions are:
Are there any documented or undocumented exceptions that allow this kind of behavior after force-quit?
Could this be a bug or a behavior change in recent iOS versions? (I am observing this on iOS 18.3, 18.4, and 18.5)
Any insights, experiences, or clarifications from Apple engineers or fellow developers would be greatly appreciated.
Thank you!
First, our app communicates with our blood glucose monitor (CGM) using Bluetooth Low Energy (BLE).
On an iPhone 14 Pro with iOS 26.0.1, Bluetooth communication works properly even when the app is in the background and locked. Even if the phone and CGM are disconnected, the app continues to scan in the background and reconnects when the phone and CGM are back in close proximity. It won't be dormant in the background or when the screen is locked. This effectively ensures that diabetic users can monitor their blood glucose levels in real time.
However, after using iOS 26.0.1 on the iPhone 17, we've received user feedback about frequent disconnections in the background. Our logs indicate that Bluetooth communication is easily disconnected when switching to the background, and then easily dormant by the system, especially when the user's screen is locked. This situation significantly impacts users' blood glucose monitoring, and users are unacceptable. What can be done?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
IOBluetooth
Background Tasks
Core Bluetooth
Hello,
I'm trying to use multiple Background Assets Packs to host map tiles.
This is problematic for a few reasons.
MKTileOverlay requires a method that returns a URL.
AssetPackManager.shared.url() throws, but it's unrelated to the url. It will return a URL even if it points to nothing.
There's no name-spacing. Everything appears to be flattened. (See Error below)
Simultaneously, this also is not the case as the documentation states: if there’s a path collision across multiple asset packs, then it’s undefined from which asset pack an individual file will be resolved.
AssetPackManager.shared.url() doesn't have an optional parameter to explicitly declare the asset pack you want to access, like AssetPackManager.shared.contents(at: FilePath) does
For example, I have multiple different tiles I'm trying to overlay for z: 10, x: 239, and y: 414.
Foo/10/239/414.png
Bar/10/239/414.png
And even when explicitly stating the fold directory, it appears that the assets are flattened down. As I'm receiving this error.
The URL for “Foo/10/239/414.png” couldn’t be retrieved: “414.png” couldn’t be copied to “239” because an item with the same name already exists.
Hello everyone,
I’m a new developer still learning as I go. I’m building a simple watchOS app that tracks Apple Watch battery consumption, records hourly usage data, and uses that information to predict battery life in hours.
I’ve run into an issue where background refresh completely stalls after charging and never recovers, regardless of what I do. The only way to restore normal behavior is to restart the watch.
Background refresh can work fine for days, but if the watch is charging and a scheduled background refresh tries to run during that period, it appears to be deferred—and then remains in that deferred state indefinitely. Even reopening the app or scheduling new refreshes doesn’t recover it.
Has anyone else encountered this behavior? Is there a reliable workaround?
I’ve seen a few reports suggesting that there may be a regression in scheduleBackgroundRefresh() on watchOS 26, where tasks are never delivered after certain states.
Any insights or confirmations would be greatly appreciated. Thank you!
Hi all,
May I please ask for an official clarification or documentation reference from Apple regarding this scenario:
Is it possible for an iOS app to automatically launch or open a specific screen when a push notification is received — while the app is in the background or terminated (killed) state?
I understand that for most cases, user interaction (such as tapping the notification) is required before the app can show UI. However, I’d like to confirm whether this is also true for time-sensitive or critical alert notifications, including emergency use cases (e.g. public safety alerts).
Specifically:
Can a critical alert notification directly launch the app or present a view controller?
Or is user interaction always required before the app can present any UI, even with the critical alert entitlement?
I would appreciate if anyone — especially Apple staff or engineers — could share an official Apple document or statement that confirms this behavior.
Thank you very much!
(Use case context: I’m developing an emergency broadcast feature for a property management / tenant app.)
Topic:
App & System Services
SubTopic:
Notifications
Tags:
APNS
User Notifications
PushKit
Background Tasks
Hello,
I’m developing a HealthKit-based fitness app in React Native that observes step count changes and uploads the latest totals to a remote server.
I’m currently using HKObserverQuery with background delivery enabled (enableBackgroundDelivery(for:frequency:.immediate)), and the behavior works correctly while the app is running in the background or foreground.
Whenever new step data is written to HealthKit, the app wakes up, reads the latest data, and sends it to my HTTPS endpoint using URLSession.shared.dataTask inside the observer callback.
However, I’ve noticed the following issue:
1. If the user swipes up (force-quits) the app from the app switcher, the observer queries stop firing entirely.
2. In this state, even though HealthKit continues collecting step data from the device or Apple Watch, my app no longer receives those background deliveries until the user opens the app again.
What I would like to achieve is:
When the app is terminated (swiped up), and there are new step count updates in HealthKit, my app should still be able to receive those updates or be relaunched to handle them — similar to how some health companion apps continue syncing data and sending notifications even after being force-quit.
So I have a few questions:
Is this limitation expected — i.e., does iOS intentionally block HKObserverQuery background deliveries after a user force-quits the app?
2. Are there any special entitlements, background modes, or Apple-approved mechanisms that allow a health or medical app to continue receiving HealthKit changes even after a force-quit?
3. If not, what is the recommended architecture for apps that need to process HealthKit data continuously and send it to a backend server? For example, should such apps rely on server-side push notifications or CloudKit sync once the user reopens the app?
My current goal is to ensure step count changes are uploaded reliably even if the app is killed, but I want to stay within the system’s supported behaviors and privacy constraints.
Any clarification or guidance from Apple engineers or others who have implemented continuous HealthKit sync (like companion or medical apps) would be greatly appreciated.
Thank you.
Topic:
App & System Services
SubTopic:
Health & Fitness
Tags:
Health and Fitness
HealthKit
Background Tasks
I have several combine pipelines in my watch and iPhone app. While background tasks on the iPhone work correctly (the combine pipelines all activate), on the watch the pipelines do not get activated. I have an internal log reporting that data is being fed to the sources but is not propagating to the sinks.
Thoughts?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
watchOS
Combine
Background Tasks
Hello,
My watchOS app has been performing fine by requesting background app refresh and then requesting any new data from health kit in the background so that the widget can be updated. However, on watchos26 I have been unable to read data in the background, with any query returning zero results. That same data is clearly read just fine while in the foreground. Can anyone assist?
Issue:
I am making an application that stores data locally from notifications fired from the server. Everything works fine in the foreground but the background is having problems with not being triggered when notifications are fired.
So we tried firing 2 notifications at the same time, including default and silent types. But the problem continues to arise on ios 18, when firing multiple times like that, the trigger is not handling all notifications, leading to data loss. I tried on ios 15 and it worked fine.
Environment:
Device or Simulator: Iphone 11 pro max (iOS 18.3.2
Steps to Reproduce:
Open app, allow received notification.
Move app to background mode or terminate app.
Sent 2 notifications:
a. Default notification payload:
{
"aps": {
"content-available": 1
},
”notification”: {…},
“alert”: {..},
“data": "some_value"
}
b. Silent notification payload:
{
"aps": {
"content-available": 1
},
”data": "some_value"
}
What I've Tried:
Trigger notification in function:
application(_:didReceiveRemoteNotification:fetchCompletionHandler:)
Handle write data to local storage in above function, put it in background thread also.
Thanks in advance!
Topic:
App & System Services
SubTopic:
Notifications
Tags:
APNS
Cloud and Local Storage
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,
An application I am working on would like to schedule push notifications for a medication reminder app. I am trying to use BGTaskScheduler to wake up periodically and submit the notifications based on the user's medication schedule.
I set up the task registration in my AppDelegate's didFinishLaunchingWithOptions method:
BGTaskScheduler.shared.register(
forTaskWithIdentifier: backgroundTaskIdentifier,
using: nil) { task in
self.scheduleNotifications()
task.setTaskCompleted(success: true)
self.scheduleAppRefresh()
}
scheduleAppRefresh()
I then schedule the task using:
func scheduleAppRefresh() {
let request = BGAppRefreshTaskRequest(identifier: backgroundTaskIdentifier)
request.earliestBeginDate = Date(timeIntervalSinceNow: 60 * 1)
do {
try BGTaskScheduler.shared.submit(request)
} catch {
}
}
In my testing, I can see the background task getting called once, but if I do not launch the application during the day. The background task does not get called the next day.
Is there something else I need to add to get repeated calls from the BGTaskScheduler?
Thank You,
JR
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Background Tasks
User Notifications
Hello, appreciate any help here.
Objective: perform a scoped write to a removable block device (using low-level system frameworks in C).
Issue: launchd-run privileged helper (as root) denied permission to open block device. Manual 'sudo ./helper' call succeeds, however.
Importantly: the entire process works flawlessly if the main app is granted Full Disk Access in Privacy & Security. However, this should be completely unnecessary for this objective, as scoped access should be sufficient, and FDA is in fact not required for other apps which perform this task.
Architecture and flow:
Main GUI process collects ISO path and target removable device path (queried via IOKit).
Main GUI process installs a Privileged Helper via SMJobBless.
The Privileged Helper is started on demand by launchd as root (UID 0, EUID 0).
Main GUI process communicates selected ISO and device paths to Privileged Helper via XPC.
Privileged Helper conducts security and sanity checks, unmounts volumes from target device via DiskArbitration.
Privileged Helper obtains file handles to ISO and target block device (e.g.: "/dev/disk4").
Privileged Helper performs a byte-by-byte write to the target block device.
Problematic area:
Simplified example using C syscalls (via Zig):
const path = "/dev/disk5";
// Note that even with readonly flag this fails
const fd = c.open(path, c.O_RDONLY, @as(c_uint, 0));
defer _ = c.close(fd);
if (fd < 0) {
const err_num = c.__error().*;
const err_str = c.strerror(err_num);
log("open() failed with errno {}: {s}", .{ err_num, err_str });
}
Output (when run by launchd - UID 0, EUID 0, domain: system):
open() failed with errno 1: Operation not permitted
Simplified example with Zig open interface:
const directory = try std.fs.openDirAbsolute(deviceDir, .{ .no_follow = true });
const device = try directory.openFile("/dev/disk5", .{ .mode = .read_write, .lock = .exclusive });
errdefer device.close();
Output (when run by launchd - UID 0, EUID 0, domain: system):
Error: error.AccessDenied
Running the same examples by manually launching the binary with a test argument succeeds:
sudo ./helper "/dev/disk5"
...
Notable points:
Both Main GUI process and the Privileged Helper binary are codesigned (via codesign ...).
Privileged Helper has both Info.plist and Launchd.plist symbols exported into its binary.
Privileged Helper has no codesign flags (e.g.: for hardened runtime or others): CodeDirectory v=20400 size=8130 flags=0x0(none) hashes=248+2 location=embedded
Output of sudo launchctl print system/<helper-bundle-id> shows nothing of interest to indicate any security restrictions.
Appreciate any advice here!
Topic:
App & System Services
SubTopic:
Core OS
Tags:
Background Tasks
Disk Arbitration
Files and Storage
Recently, I've noticed that background Bluetooth scanning stops when I move an app to the background on an iPhone 17 device with Bluetooth 6. I'm curious about a solution. Background Bluetooth scanning doesn't stop on devices older than iOS 26, or on devices that were updated from an iPhone 17 or earlier to iOS 26.
I created my app. One of its functionality is receive remote notification in the background (it receives it from Firebase Cloud Messaging via APNS) and replies with device location data. This is "boat tracking and alarm" type of app.
It worked well both on my iPhone (where I use the same Apple ID as on developer's account) and on my son's iPad (different Apple ID). After the first review, when app was rejected with some remarks, background remote notifications completely stopped working on my iPhone. It looks like my iPhone put the app in permanent sleep. It never receives the background notifications. It receives them though in 2 case:
when I open the app (it is no longer in background)
when location is changed (it wakes app in the background). But the app should also respond when the device is stable at the position (I use both: precise and Significant Location Change. In the latter case changes are very rare). Btw, I scheduled a background task, not location, and it also never gets executed, so this workaround does not work.
I describe it, so any Apple engineer does not get confused, verifying that these remote notifications reach the device. NO, they never get through when app is in the background (THIS IS THE PROBLEM), not that they are never delivered (the are, in the foreground). And the proof that it is not a problem with the app or remote notification construction is:
they work on another drives (iPad) with no issues. Sometimes they are very delayed, sometimes almost instant. But usually they work.
they worked the same way on my iPhone (with my developer's Apple ID) before the first rejection, and I haven't messed with messaging functionality since then.
Now I am over with the last hope I had. I finally got my app release in App Store. I hoped official version would release some blockade my iOS put on my app. But unfortunately not. Official version works the same way as the test one. It works fine (receiving notifications in the background) on my son's iPad and it does not receive any background notification on my iPhone (100% block rate).
Can anyone help me how can I reset my apps limits, the iOS created for my app? It seems that the rejection was a sparkle here - this is just a hint. I can provide any system logs for Apple engineers from both devices (iPhone and iPad) if you would like to check this case.