General: Forums subtopic: App & System Services > Core OS Forums tags: Files and Storage, Foundation, FSKit, File Provider, Finder Sync, Disk Arbitration, APFS Foundation > Files and Data Persistence documentation Low-level file system APIs are documented in UNIX manual pages File System Programming Guide archived documentation About Apple File System documentation Apple File System Guide archived documentation File system changes introduced in iOS 17 forums post On File System Permissions forums post Extended Attributes and Zip Archives forums post Unpacking Apple Archives forums post Creating new file systems: FSKit framework documentation Building a passthrough file system sample code File Provider framework documentation Finder Sync framework documentation App Extension Programming Guide > App Extension Types > Finder Sync archived documentation Managing storage: Disk Arbitration framework documentation Disk Arbitration Programming Guide archived documentation Mass Storage Device Driver Programming Guide archived documentation Device File Access Guide for Storage Devices archived documentation BlockStorageDeviceDriverKit framework documentation Volume format references: Apple File System Reference TN1150 HFS Plus Volume Format Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com"

Hi, Is it possible to create an App in USB portable flash drive, which can automatically call iPhone file app, to allow iPhone file app access the content of flash drive, when USB portable flash plug into iPhone?

https://developer.apple.com/documentation/fileprovider/nsfileproviderpartialcontentfetching/3923718-fetchpartialcontents fetchPartialContents(for:version:request:minimalRange:aligningTo:options:completionHandler:) I need to use this function to fetch contents of the files partially. But it seems I'm just unable to receive any callback when i try to open the file via double click on finder. I've tried to open files of different types and sizes but still i'm defaulting back to fetchContents(for:version:request:completionHandler:) . I've been thinking if there are any specific configurations or requirements that i have to meet , so i could trigger this callback function for all the fetch Operations for files ? If No, then where am i going wrong ?

I am trying to populate the Finder comment field from extendedAttributes with the code bellow but it doesn't work. Any idea why ? var extendedAttributes: [String : Data] { var attrs = [String: Data]() let comment = self.caption do { let xmlPlistData = try PropertyListSerialization.data(fromPropertyList: comment as Any, format: .xml, options: 0) attrs["com.apple.metadata:kMDItemFinderComment"] = xmlPlistData } catch { NSLog("Error during plist conversion: \(error)") } return attrs }

I'm not sure if I have found a bug with iOS or if it's just unexpected behavior with my implementation. I have a gomobile library that sets up a local http server. It needs to be able to write to temporary storage. If I use the shared library from my main apps process it can write to the file manager.default temporary storage. while Xcode is running a debug session I can use that same process from my file provider replicated extension and it works fine. However I realized running my file provider extension where it starts the gomobile shared library directly instead of first from my app the library fails to write anything to the file provider manager default temporary storage or the file provider manager for my file provider domain temporary storage or even the app group library. it is odd, because I have a swift URL extension that confirms the temporary storage can be written to from swift. I have monitored console logs for fileproviderd, my file extension and have tried writing data to a log file. nothing seems to catch exactly what causes the file provider extension to crash and restart. I also cannot keep the shared gomobile server running in the background on iOS even if I were to force the user to "authenticate" with the main app first. Im pretty sure the file provider extension needs to run the gomobile library for it to work right. I'm wondering if something may be wrong with the iOS sandbox that could be preventing the file provider extension to let a c based gomobile shared library from accessing the temporary storage. Any guidance for further things to try would be greatly appreciated. I have tried every avenue I can think of. I cannot run just the appex itself on either my m4 pro MacBook or my iPhone so attaching the debugger has been tricky and I don't see much in the way of useful logs in console app either just a swarm of noise. Im fairly confident it's an issue to writing to temporary storage from the gomobile c library and not much else. App was working great on macOS designed for iPad which just seemed rather ironic that an iOS code base runs better on macOS than it was able to on my iPhone 16 pro max. Like im all for the sandbox I just wish it didn't treat c level gomobile libraries different than it treats the swift code itself.

Hi We have a non-replicated Files Provider extension on iOS that creates multiple domains. I've noticed that iOS typically creates one process per domain, so I would assume that each process is meant to handle one domain. However, in practice, is seems that calls for any domain can occur in any process. I'm wondering whether there is supposed to be a mapping, implying there might be something wrong with the code, or whether we shouldn't make assumptions about domain:process mapping. Thanks for any info you can provide.

I have FileProvider based MacOS application, where user is trying to copy the folder having mix of small and large files. Large files are having size ~ 1.5 GB from FileProvider based drive to locally on Desktop. Since the folder was on cloud and not downloaded the copy action triggered the download. Small files were downloaded successfully however during large file download the URLSession timed out. We are using default timeout for URLSession which is 1 min. I tried to capture logs Console.app where i found FileProvider daemon errors. PFA Solutions tried so far: Increased timeout for URLSession from 5 to 10 mins - configuration.timeoutIntervalForRequest Set timeout for resource - configuration.timeoutIntervalForResource It happens when we have low network bandwidth. Network connectivity is there but the bandwidth is low. Any clue by looking at these errors?

I've already searched extensively on Apple Developer Forums and Stack Overflow, and didn't really find what I need or I missed it. I'm developing a macOS music player app that uses cuesheet files paired with audio files. The core functionality is working, opening and playing files works without issues, but I'm struggling with implementing proper file handling features due to my limited experience with UI frameworks. The current state of my app is intentionally simple: Single window interface representing a music player with track list Opening cuesheet files changes the “disc” and updates the window Built with SwiftUI (not AppKit) Not created as a Document-Based app since the user doesn't need to edit, save, or work with multiple documents simultaneously What I Need to Implement: Open Recent menu that actually works Recent files accessible from Dock menu Opening cuesheet files from Finder Drag-and-drop cuesheet files onto app window (lower priority) Problems I've Encountered: I've tried multiple approaches but never achieved full functionality. The closest I got was an “Open Recent” menu that: Only updated after app relaunch Its drop-down kept closing while music was playing My Questions Is it possible purely in SwiftUI? Is there documentation I'm missing? I feel like I might be overcomplicating this. I'm open to alternative approaches if my current direction isn't ideal: Should I redesign as Document-Based? Since I apparently need NSDocumentController, would it be better to start with a Document-Based app template and disable unwanted features, and how? Should I mix AppKit with SwiftUI? While SwiftUI has been wonderful for my main window, it's becoming frustrating for other UI parts, especially menus. Would using AppKit for menus and keeping SwiftUI for the main interface be a reasonable approach? I thought this would be straightforward: Customize the .fileImporter with the proper logic of what to do with the files Call NSDocumentController.shared.noteNewRecentDocumentURL(url) so the Open Recent menu is created a populated with opened files. Maybe it really is that simple and I've gotten lost down a rabbit hole? UI programming is quite new to me, so I might be missing something obvious. Any guidance, code examples, or pointing me toward the right documentation would be greatly appreciated!

Hello, I am currently investigating if we can disable usage of QUIC on application level. I know we can set enable_quic from /Library/Preferences/com.apple.networkd.plist to false but it will have a global impact since this is a system file, all the applications on machine will stop using QUIC. I don't want that. What i am looking for is to disable QUIC only for my application. Is there any way i can modify URLSession object in my application and disable QUIC? or modify URLSessionConfiguration so system will not use QUIC?

This concerns file provider framework on macOS. Some users of our application (Egnyte.app) report that they have problems downloading dataless files. When a file reaches invalid state, trying to open or download it through Finder results in "Invalid argument" alert (see example-recording.mp4). At the same time our FileProvider extension receives no fetchContents or fetchPartialContents calls. A step-by-step set of instructions to reproduce the problem (if possible) So far we don't have clear reproduction steps. The issue is easily reproducible, for multiple files, for some of our customers. See attached sysdiagnose and recording. What results you expected Our extension receives a request to download the file. File downloads and opens successfully. What results you actually saw No download request made to our File Provider extension. File doesn't open, Finder alert instead. PLEASE NOTE: Before recording and collecting sysdiagnose we installed FileProvider.mobileconfig, slightly modified official profile that we attach. Example reproduction happens 8:33 into full-recording.mp4, around 17:01:18 / 17:01:19 machine’s time. Shared sysdiagnose and recordings come from one of our customers, they permitted us to share the data. In the recording they try to open files with multiple 3rd party applications (Vectorworx, Office PowerPoint) and those opens fail with alerts from those applications. We have similar reports from customers using Adobe apps.

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 } }

I am building a Vision OS app that includes a File Provider and File Provider UI extension. Both work great in simulator. When uploading to TestFlight, this message is shown: Unsupported Platform. The extension bundle [...]/PlugIns/File ProviderUI.appex is not supported for this platform. If I exclude the File Provider UI extension from the build, it is accepted. If I even include a hello-world File Provider UI extension, the error shown above is returned by ASC. There is contradicting documentation on this subject: https://developer.apple.com/documentation/technologyoverviews/app-extensions states that File Provider UI extension is not supported on Vision OS, so that explains ASC behavior https://developer.apple.com/documentation/FileProviderUI (and all other framework docs) states that File Provider UI extension is supported on Vision OS, so that explains why it works on simulator. Now, which of these two is correct? My best guess at this point is that ASC's logic follows the first document linked above, while the OS and framework actually follow the second. The same discrepancy seems to hold for macOS, but I'm currently focusing on Vision OS. Ideas? Anybody using a File Provider UI extension on Vision OS?

We are creating a Replicated FileProvider based application, where we want to handle different types of errors. As per doc: https://developer.apple.com/documentation/fileprovider/synchronizing-files-using-file-provider-extensions?language=objc#Handle-errors-elegantly NSFileProviderErrorNotAuthenticated is a resolvable error, and once we report it, the system throttles the sync operation until something (most likely the app or extension) calls signalErrorResolved(:completionHandler:) to signal that the user or the server resolves the error. But this is not happening in our app, see below the sample code snippet (showing just error related code to keep it concise): NSProgress* MacFileProvider::modifyItem(....) { NSProgress *nsProgress = [[NSProgress alloc] init]; nsProgress.totalUnitCount = NSURLSessionTransferSizeUnknown; NSError *error = [NSError errorWithDomain:NSFileProviderErrorDomain code:NSFileProviderErrorNotAuthenticated userInfo:nil]; completionHandler(nil, 0, false, error); return nsProgress; } Observed behaviour: On making local edits to a file, though this function returns resolvable error, this function is being called multiple times with retry back-off interval. Also, this function is called when we edit other files as well. Expected behaviour: As we are returning resolvable error, system should have throttled the operation until we resolve the error. So, all sync operation should have stopped for any item. Can someone please help understand this behaviour difference, and how to achieve the expected behaviour.

I am writing an NSFileProviderReplicatedExtension for my app. Every once in a while it will get to a point where NSFileProviderManager.getDomainsWithCompletionHandler { domains, error in DispatchQueue.main.async { if let error = error { completion(.failure(.domainQueryFailed(error))) } else { completion(.success(domains)) } } } this always fails, once this happens then regardless of what I do - clean build, restart machine, uninstall plugin nothing works. The only way to get back to a wokring state is a full reinstall of the OS. It seems like when this happens Finder gets to a weird irrecoverable state that only a restart can fix. When it fails the error is always : The application cannot be used right now. the only way out is reisntall the OS. When this happened last time, I was advised to the use the debugging profile: https://developer.apple.com/forums/thread/797053 I now have that and have the log which is 300MB file, where do I upload it to? My machine is in that state, is there anything else I can run or diagnose to address this?

I face this issue only on macOS 26 and only on the Intel architecture. I'm unable to download files from a file provider's folder when I make them read-only. STEPS TO REPRODUCE Download the sample from https://developer.apple.com/documentation/fileprovider/synchronizing-files-using-file-provider-extensions?language=objc Follow the steps on the page to configure the project. Build the project. Run it. Add a domain. Open the domain's folder in the Finder. Move a file to the domain's folder. Right-click on the file in the domain's folder and select "Remove Download". Close the Finder's window with the domain's folder and kill all the "Provider" processes to get rid of running instances of the extension. Change Item's capabilities in Item.swift to make the items read-only: var result: NSFileProviderItemCapabilities = [ .allowsContentEnumerating, .allowsReading ] Rebuild the project and run it. Open the domain's folder and try to drag and drop the file from the extension's folder to, let's say, the Desktop folder. EXPECTED RESULT The file is copied ACTUAL RESULT A dialog pops up with text "The file “filename” cannot be downloaded. Do you want to skip it?" Stop/Skip

I'm working on an iOS document-based app. It uses ReferenceFileDocument and custom creation of documents via DocumentGroupLaunchScene + NewDocumentButton. It works fine when I use the plain NewDocumentButton("Whatever") (without any more arguments), but when I want to perform additional setup via preapreDocumentURL or even just add a contentType it gives such output in the console when I hit it: Content serialization failed, document won't be saved. UTType.replayable is correctly wired up in the plist. It looks like a bug in the SDK, but maybe there is a chance that I'm doing something wrong? Here's a code: import SwiftUI import UniformTypeIdentifiers import Combine @main struct MyApp: App { var body: some Scene { DocumentGroup { Document() } editor: { documentConfiguration in EmptyView() } DocumentGroupLaunchScene("Yoyo") { NewDocumentButton(contentType: .replayable) { return URL(string: "whatever, it doesnt even go there...")! } } } } final class Document: ReferenceFileDocument { static var readableContentTypes: [UTType] { [.replayable] } @Published var x = 0 init() {} init(configuration: ReadConfiguration) throws {} func snapshot(contentType: UTType) throws -> Data { Data() } func fileWrapper(snapshot: Data, configuration: WriteConfiguration) throws -> FileWrapper { .init(regularFileWithContents: snapshot) } } extension UTType { static var replayable: UTType { UTType(exportedAs: "com.whatever.yo") } }

We are creating a Replicated FileProvider based application, where we need to change folder icons for root level folders. I tried below two approaches. This using NSFileProviderDecorations + Custom UTType, this changed the UI as shown: This using Custom UTType, this had no UI change: How can we change the default folder icon, to our custom icon?

I'm new to swift and iOS development. I'm trying to create a file provider extension for my app. I have able to use createItem, modifyItem, fetchContents functions. But when I try to add a GarageBand file or a big size mp3 file(18 Mb) I can see multiple upload is happening. I checked the FruitBasket project where they are doing chunked upload when file size is more than 100 Mb. How do I fix this to only one upload? I'm getting suggestions like I have to do debounce upload but that seems not a proper solutions.

I am currently encountering a problem: during the process of uploading a large file, I have moved the file that was not successfully uploaded to the trash can. These two operations have been tested to be serial (triggering the 'create Item' callback first, followed by the 'modify Item' callback), which means that the file must be uploaded before it can be moved to the recycle bin (which can also result in the file being stored in the cloud recycle bin). I want to implement: directly interrupt this upload process and then do not complete the upload. How can I achieve this? Please help me. Thank you

I found that the enumerateItems function is only called when a directory is opened for the first time. If the same directory is opened in the future, enumerateItems will not be called again. Can you set or actively trigger the call to the enumerateItems function