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!
Processes & Concurrency
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How to execute code on main app when interacted with a live activity, given that they are already interactable.
is there a way without opening the app?
what are the best ways?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Extensions
WidgetKit
ActivityKit
We've seen a recent increase in background terminations:
blue - System Pressure
orange - Task Timeout
I'm trying to understand the increase in system-pressure terminations, since there's no corresponding increase in memory at suspension. Are there other system resources for which iOS will terminate an app?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Organizer Window
Background Tasks
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!
I have an app that uses background audio recording. From what others say, I have enabled the audio background mode to keep the audio session active, and this worked. But when submitting the app to the app store, the app was rejected because the audio background mode is only supposed to be used for audio playback.
How do I create this background mode while following Apple's guidelines?
I have followed this post for creating a Launch Agent that provides an XPC service on macOS using Swift-
post link - https://rderik.com/blog/creating-a-launch-agent-that-provides-an-xpc-service-on-macos/
In the swift code the interface of the XPC service is defined by protocols which makes the code nice and neat. I want to implement the XPC service using C APIs for XPC, and C APIs send and receive messages using dictionaries, which need manual handling with conditional statements.
I want to know if its possible to go with the protocol based approach with C APIs.
I am trying to create an app bundle with an xpc service. The main app creates a keychain item, and attempts to share (keychain access groups) with the xpc service it includes in its bundle. However, the xpc service always encounters a 'user interaction not allowed' error regardless of how I create the keychain item. kSecAttrAccessiblei is set to kSecAttrAccessibleWhenUnlockedThisDeviceOnly, the keychain access group is set for both the main app and the xpc service and in the provisioning profile. I've tried signing and notarizing.
Is it ever possible for an xpc service to access the keychain? This all on macos 15.5.
When my app enter to background, I start a background task, and when Expiration happens, I end my background task. The code likes below:
backgroundTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
dispatch_async(dispatch_get_main_queue(), ^{
if (backgroundTask != UIBackgroundTaskInvalid) {
[[UIApplication sharedApplication] endBackgroundTask:backgroundTask];
backgroundTask = UIBackgroundTaskInvalid;
[self cancel];
}
});
}];
When the breakpoint is triggered at the endBackgroundTask line, I also get the following log:
[BackgroundTask] Background task still not ended after expiration handlers were called: <UIBackgroundTaskInfo: 0x282d7ab40>: taskID = 36, taskName = Called by MyApp, from MyMethod, creationTime = 892832 (elapsed = 26). This app will likely be terminated by the system. Call UIApplication.endBackgroundTask(:) to avoid this.
The log don't appear every time, so why is that? Is there something wrong with my code?
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?
my app need tracking location all the time both foreground and background. Please suggest how to prevent the app from being terminated. or detect when app is terminated.
I have BGProcessingTask & BGAppRefreshTask working fine. The main purpose of my use of BGProcessingTask is to upload a file to AWS S3 using multipart/form-data. I have found that any file above about 2.5MB times out after running almost four minutes. If I run the same RESTful api using curl or Postman, I can upload a 25MB file in 3 seconds or less.
I have tried to deliberately set .earliestBeginDate to 01:00 or 02:00 local time on the iPhone, but that does not seem to help.
I use the delegate (yes, I am writing in Objective C) - URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend: and find that the iOS system uploads about 140kB every 15 seconds or so.
I am looking for recommendations or insight into how I might enable uploads of 25MB files. I would be happy it I could do just one a day for my use case.
I provide code on how I set up the NSURLSession and NSURLSessionDownloadTask, as it is my guess that if there is something that needs to be modified it is there.
I have to believe there is a solution for this since I read in many posts here and in StackOverflow how developers are using this functionality for uploading many, many files.
NSURLSessionConfiguration *sConf = [NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:bkto.taskIdentifier];
sConf.URLCache = [NSURLCache sharedURLCache];
sConf.waitsForConnectivity = YES;
sConf.allowsCellularAccess = NO;
sConf.networkServiceType = NSURLNetworkServiceTypeVideot;
sConf.multipathServiceType = NSURLSessionMultipathServiceTypeNone;
sConf.discretionary = YES;
sConf.timeoutIntervalForResource = kONEHOURINTERVAL;
sConf.timeoutIntervalForRequest = kONEMINUTEINTERVAL;
sConf.allowsExpensiveNetworkAccess = NO ;
sConf.allowsConstrainedNetworkAccess = NO;
sConf.sessionSendsLaunchEvents = YES;
myURLSession = [NSURLSession sessionWithConfiguration:sConf delegate:self delegateQueue:nil];
And then later in the code...
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:pth]];
request.HTTPMethod = kHTTPPOST;
request.HTTPBody = [NSData my body data];
request.timeoutInterval = 60;
[request setValue:@"*/*" forHTTPHeaderField:@"Accept"];
[request setValue:@"en-us,en" forHTTPHeaderField:@"Accept-Language"];
[request setValue:@"gzip, deflate, br" forHTTPHeaderField:@"Accept-Encoding"];
[request setValue:@"ISO-8859-1,utf-8" forHTTPHeaderField:@"Accept-Charset"];
[request setValue:@"600" forHTTPHeaderField:@"Keep-Alive"];
[request setValue:@"keep-alive" forHTTPHeaderField:@"Connection"];
NSString *contType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",bnd];
[request setValue:contType forHTTPHeaderField:@"Content-Type"];
[request addValue:[NSString stringWithFormat:@"%lu",(unsigned long)myData.length] forHTTPHeaderField:@"Content-Length"];
and here are a few lines from my logs to show the infrequent multi-part uploads of only small chunks of data by the iOS system:
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: bytesSent = 393,216
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: totalBytesSent = 393,216
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: task = BackgroundDownloadTask <76A81A80-4703-4686-8742-A0048EB65108>.<2>, time Fri Mar 7 16:25:27 2025
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: bytesSent = 131,072
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: totalBytesSent = 524,288
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: task = BackgroundDownloadTask <76A81A80-4703-4686-8742-A0048EB65108>.<2>, time Fri Mar 7 16:25:42 2025
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: bytesSent = 131,072
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: totalBytesSent = 655,360
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: task = BackgroundDownloadTask <76A81A80-4703-4686-8742-A0048EB65108>.<2>, time Fri Mar 7 16:25:56 2025
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: bytesSent = 131,072
-[BKSessionManager URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:]: totalBytesSent = 786,432
Hello 👋
Our team added com.apple.security.temporary-exception.apple-events: com.apple.Terminal recently to our Mac app to be able to tell the terminal to execute a specific command line automatically for the user when clicking a button but we've been rejected during review because of this entitlement so for now we've deleted it and deleted the associated feature.
It concerns the following feature (see attachment).
Context:
Among other things the application enable to review pull request changes (remote) and we would like a button to automatically clone the pull request on disk when user click a button. We would like to use terminal for security reason as when cloning using git command we need ssh keys or other credential and there's no reason (rather than technical ones) that the user provide us such private information that is stored in the ~/.ssh. We prefer think the other way around and tell the user what to execute instead (no credentials involved or shared).
We referred to: https://developer.apple.com/library/archive/documentation/Miscellaneous/Reference/EntitlementKeyReference/Chapters/AppSandboxTemporaryExceptionEntitlements.html
I admit it's unclear for me if this will imply a 100% rejection or if these entitlements are deprecated.
Is "com.apple.security.temporary-exception.apple-events: com.apple.Terminal" an entitlement that is reserved for special Apple partners ?
Is it an entitlement that we should demonstrate usage first ? Or should we completely remove the feature if we distribute through the App Store ?
Is Apple advice for other APIs to develop such features (execute command line for the user) when distributing through the App Store ?
As said we've disabled the feature for now.
Thank you in advance for those who will take time to answer this,
I’m currently porting a Chrome Extension to Safari and integrating it with native messaging in a Safari Web Extension. As part of this, I’m building a proxy to forward messages between the web extension and a socket in another application, both ways. Additionally, the socket occasionally broadcasts messages that also need to be sent to the web extension.
The issue I’m facing is that the app extension terminates whenever I call context.completeRequest(returningItems: nil), which prevents me from listening for incoming messages from the socket (I'm using the Network Framework). To work around this, I’ve tried not calling context.completeRequest(returningItems: nil), which keeps the app extension running. However, I’m unsure if this is the right approach—currently, I’m simply ignoring the response and relying entirely on SFSafariApplication.dispatchMessage.
According to the documentation, the app extension lifecycle ends when the system terminates it, but I need to keep the socket listener active.
Has anyone encountered a similar issue, or does anyone have suggestions for maintaining the socket connection while adhering to the app extension lifecycle?
Any insights would be greatly appreciated!
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Network
Safari Services
Safari Extensions
Testing Environment:
iOS: 26.0 Beta 7
Xcode: Beta 6
Description:
We are implementing the new BGContinuedProcessingTask API introduced in iOS 26. We have followed the official documentation and WWDC session guidance to configure our project.
The Background Modes (processing) and Background GPU Access capabilities have been added in Xcode.
The com.apple.developer.background-tasks.continued-processing.gpu entitlement is present and set to in the .entitlements file.
The provisioning profile details viewed within Xcode explicitly show that the "Background GPU Access" capability and the corresponding entitlement are included.
Despite this correct configuration, when running the app on supported hardware (iPhone 16 Pro), a call to BGTaskScheduler.supportedResources.contains(.gpu) consistently returns false.
This prevents us from setting request.requiredResources = .gpu. As a result, when the BGContinuedProcessingTask starts without the GPU resource flag, our internal Metal-based exporter attempts to access the GPU and is terminated by the system, throwing an IOGPUMetalError: Insufficient Permission (to submit GPU work from background).
We have performed extensive debugging, including a full reset of the provisioning profile (removing/re-adding capabilities, toggling automatic signing, cleaning build folders, and reinstalling the app), but the issue persists. This strongly suggests a bug in the iOS 26 beta where the runtime is failing to correctly validate a valid entitlement.
Additionally, we've observed inconsistent behavior across devices. On an A16-based iPad, the task submits successfully (BGTaskScheduler.submit does not throw an error), but the launch handler is never invoked by the system. On the iPhone 16 Pro, the handler is invoked, but we encounter the supportedResources issue described above. This leads us to ask for clarification on the exact hardware requirements for this feature. We hypothesize that it may be limited to devices that support Apple Intelligence (A17 Pro and newer). Could you please confirm this and provide official documentation on the device support criteria?
Steps to Reproduce:
Create a new Xcode project.
In Signing & Capabilities, add "Background Modes" (with "Background processing" checked) and "Background GPU Access".
Add a permitted identifier (e.g., "com.company.test.*") to BGTaskSchedulerPermittedIdentifiers in Info.plist.
In application(_:didFinishLaunchingWithOptions:) or a ViewController's viewDidLoad, log the result of BGTaskScheduler.shared.supportedResources.contains(.gpu).
Build and run on a physical, supported device (e.g., iPhone 16 Pro).
Expected Results:
The log should indicate that BGTaskScheduler.shared.supportedResources.contains(.gpu) returns true.
Actual Results:
The log shows that BGTaskScheduler.shared.supportedResources.contains(.gpu) returns false.
I have an XPC server running on macOS and want to perform comprehensive performance and load testing to evaluate its efficiency, responsiveness, and scalability. Specifically, I need to measure factors such as request latency, throughput, and how well it handles concurrent connections under different load conditions.
What are the best tools, frameworks, or methodologies for testing an XPC service? Additionally, are there any best practices for simulating real-world usage scenarios and identifying potential bottlenecks?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
XPC
Endpoint Security
Instruments
Performance
I work for a large medical device company.
We have a 1st party BLE enabled medical device that must be very battery efficient. To this end, if a connection is lost, the BLE radio is powered down after 60 seconds and will only turn back on when a physical button on the device is pressed.
I've been tasked with connecting to the device, staying connected to the device, and being able to retrieve data from the device upon a timed action. For instance, this could include a data read and transmission while they sleep. The key part of this is staying reliably connected for extended periods of time.
This is a BYOD setup, and we cannot control power profiles.
I would very much appreciate any information, recommendations, and/or insights into solving this problem.
Thanks!
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
External Accessory
iOS
Application Services
Core Bluetooth
When I run my app with XCode on my iPhone, and then moved into the background, I'm getting a EXC_BREAKPOINT exception after a few minutes, seemingly when iOS attempts to call my app with a BGAppRefreshTask:
Thread 23 Queue: com.apple.BGTaskScheduler (com.mycompany.MyApp.RefreshTask) (serial)
0 _dispatch_assert_queue_fail
12 _pthread_wqthread
Enqueued from com.apple.duet.activityscheduler.client.xpcqueue (Thread 23)
0 dispatch_async
20 start_wqthread
I can't quite understand the reason from this crash. In the background task, I'm attempting to update live activities. In the process, it might encounter code that calls MainActor and manipulate @Observable objects. Might that be the reason?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Swift
Background Tasks
Observation
Hi,
We are running into issues with iOS app prewarming, where the system launches our app before the user has entered their passcode.
In our case, the app stores flags, counters, and session data in UserDefaults and the Keychain. During prewarm launches:
UserDefaults only returns default values (nil, 0, false). We have no way of knowing whether this information is valid or just a placeholder caused by prewarming.
Keychain items with kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly are inaccessible, which can lead to broken business logic (the app can assume no session exists).
No special launch options or environment variables appear to be set.
We can reproduce this 100% of the time by starting a Live Activity in the app before reboot.
Here’s an example of the workaround we tried, following older recommendations:
__attribute__((constructor))
static void ModuleInitializer(void) {
char* isPrewarm = getenv("ActivePrewarm");
if (isPrewarm != NULL && isPrewarm[0] == '1') {
exit(0); // prevent prewarm launch from proceeding
}
}
On iOS 16+, the ActivePrewarm environment variable doesn’t seem to exist anymore (though older docs and SDKs such as Sentry reference it).
We also tried listening for UIApplication.protectedDataDidBecomeAvailableNotification, but this is not specific to prewarming (it also fires when the device gets unlocked) and can cause watchdog termination if we delay work too long.
Questions:
Is there a supported way to opt out of app prewarming?
What is the correct way to detect when an app is being prewarmed?
Is the ActivePrewarm environment variable still supported in iOS 16+?
Ideally, the UserDefaults API itself should indicate whether it is returning valid stored values or defaults due to the app being launched in a prewarm session.
We understand opting out may impact performance, but data security and integrity are our priority. Any guidance would be greatly appreciated.
DESCRIPTION OF PROBLEM
Logs and data from our application indicate various errors that strongly suggest that our application is being launched in a state in which the device is likely locked. We are looking for guidance on how to identify, debug, reproduce, and fix these cases.
Our application does not use any of the common mechanisms for background activity, such as Background App Refresh, Navigation, Audio, etc.
Errors we get in our logs such as "authorization denied (code: 23)" when trying to access a file in our app's container on disk (a simple disk cache for data our application uses) strongly suggest that the device is operating in a state, such as being locked, where our application lacks the requisite permissions it would normally have during operation. Furthermore, attempts to access authentication information stored in the keychain also fails. We use kSecAttrAccessibleWhenUnlocked when accessing items we store in the keychain.
We have investigated "Prewarming", as well as our notification extension that helps process incoming push notifications, but cannot find any way to recreate this behavior.
Are there any steps Apple engineers can recommend to triage and debug this?
Some additional questions that would help us:
What are all of the symptoms that we can look for if prewarming escapes the intended execution context?
What are all of the circumstances in which we would be unauthorized to access the app’s documents/file directories even if it works correctly in normal operation?
STEPS TO REPRODUCE
Unfortunately, we are unable to forcibly reproduce this behavior in our application, so we're looking for guidance on how we might simulate this behavior in Xcode / Instruments.
Are there tools that Apple provides that would allow us to simulate certain behaviors like prewarming to verify our application's functionality?
Are there other reasons our application might be launched while the device is locked? Are there other reasons we would receive security errors when accessing the keychain or disk that are unrelated to the device being locked?
Hello,
I'm running into an issue with a complex macOS application (non-AppStore) structure involving an unsandboxed system daemon and a sandboxed SSO Extension attempting to communicate via XPC Mach service.
The macOS app is composed of three main components:
Main App: unsandboxed, standard macOS application.
System Daemon: unsandboxed executable installed with a .plist to /Library/LaunchDaemons/ and loaded by launchd. It exposes an XPC Mach Service.
SSO Extension: a sandboxed Authentication Services Extension (ASAuthorizationProviderExtension).
Main App to System Daemon communication works perfectly. The unsandboxed main app can successfully create and use an XPC connection to the System Daemon's Mach service.
But SSO Extension cannot establish an XPC connection to the System Daemon's Mach service, despite using the recommended temporary exception entitlement. I have added the following entitlement to the SSO Extension's entitlements file:
<key>com.apple.security.temporary-exception.mach-lookup.global-name</key>
<array>
<string>my.xpc.service.system.daemon</string>
</array>
(The name my.xpc.service.system.daemon is the exact name registered by the System Daemon in its Launch Daemon plist's MachServices dictionary.)
When the SSO Extension attempts to create the connection, the following log output is generated:
default 08:11:58.531567-0700 SSOExtension [0x13f19b090] activating connection: mach=true listener=false peer=false name=my.xpc.service.system.daemon
default 08:11:58.532150-0700 smd [0xb100d8140] activating connection: mach=false listener=false peer=true name=com.apple.xpc.smd.peer[1575].0xb100d8140
error 08:11:58.532613-0700 smd Item real path failed. Maybe the item has been deleted?
error 08:11:58.532711-0700 SSOExtension Unable to find service status () error: 22
The error Unable to find service status () error: 22. Error code 22 typically translates to EINVAL (Invalid argument), but in this context, it seems related to the system's ability to find and activate the service for the sandboxed process.
Questions:
Is the com.apple.security.temporary-exception.mach-lookup.global-name entitlement sufficient for a sandboxed SSO Extension to look up a system-wide Launch Daemon Mach service, or are there additional restrictions or required entitlements for extensions?
The smd log output Item real path failed. Maybe the item has been deleted? seems concerning. Since the unsandboxed main app can connect, this suggests the service is running and registered. Could this error indicate a sandbox permission issue preventing smd from verifying the path for the sandboxed process?
Are there specific sandboxing requirements for Mach service names when communicating from an Extension versus a main application?
Any guidance on how a sandboxed SSO Extension can reliably connect to an unsandboxed, non-app-group-related system daemon via XPC Mach service would be greatly appreciated!