Hi, I am implementing a premium feature in my app where CloudKit syncing is available only for "Pro" users. The Workflow: Free Users: I initialize the ModelContainer with cloudKitDatabase: .none so their data stays local. Pro Upgrade: When a user purchases a subscription, I restart the container with cloudKitDatabase: .automatic to enable syncing. The Problem: If a user starts as "Free" (creates local data) and later upgrades to "Pro", the app crashes immediately upon launch with the following error: Fatal error: Failed to create ModelContainer: SwiftDataError(_error: SwiftData.SwiftDataError._Error.loadIssueModelContainer, _explanation: nil) It seems that SwiftData fails to load the existing data once the configuration changes to expect a CloudKit-backed store. My Question: Is there a supported way to "toggle" CloudKit on for an existing local dataset without causing this crash? I want the user's existing local data to start syncing once they pay, but currently, it just crashes. My code: import Foundation import SwiftData public enum DataModelEnum: String { case task, calendar public static let container: ModelContainer = { let isSyncEnabled = UserDefaults.isProUser let config = ModelConfiguration( groupContainer: .identifier("group.com.yourcompany.myApp"), cloudKitDatabase: isSyncEnabled ? .automatic : .none ) do { return try ModelContainer(for: TaskModel.self, CalendarModel.self, configurations: config) } catch { fatalError("Failed to create ModelContainer: \(error)") } }() }

Understand dataless files and how to minimize the performance impact as the system materializes them. View Technote TN3150 >

Hi, I'm using SwiftData in my app, and I want to sent data to iCloud with CloudKit, but I found that If the user turns off my App iCloud sync function in the settings App, the local data will also be deleted. A better way is maintaining the local data, just don't connect to iCloud.How should I do that? I need guidance!!! I'm just getting started with CloudKit And I would be appreciated!

I have an app that uses a Share Extension that allows the user to share videos, from Files and Photos etc., the video URL and some related data is then persisted with SwiftData and synchronized with CloudKit. This code has worked consistently for a long time although recently, with iOS 26 and recent builds of iOS 18, I have observed that the video is either not saved to SwiftData (iOS 26.0), or available locally when the app is opened on the same device where the share occurred, but not synchronized to other devices (iOS 18.7 and iOS 26.1 beta). Assuming the video is opened locally after being shared into the app, it is typically synchronized with CloudKit to other devices although it's not as reliable as it should be. Is there a reliable approach in the Share Extension to ensure that the data is saved to the local SwiftData database and then synchronized with CloudKit. I suspect it could be that the lifetime of the Share Extension has become even more constrained in recent OS updates that the process ends before it has the opportunity to save and synchronize the data. Any thoughts on how to ensure this is reliable would be greatly appreciated. The data saved is not too large as it consists only of the video URL and not the data of the video itself.

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!

Since publishing new record types to my CloudKit schema in production, a previously unchanged record type has stopped indexing new records. While records of this type are successfully saved without errors, they are not returned in query results—they can only be accessed directly via their recordName. This issue occurs exclusively in the Production environment, both in the CloudKit Console and our iOS app. The problem began on July 21, 2025, and continues to persist. The issue affects only new records of this specific record type; all other types are indexing and querying as expected. The affected record's fields are properly configured with the appropriate index types (e.g., QUERYABLE) and have been not been modified prior to publishing the schema. With this, are there any steps I should take to restore indexing functionality for this record type in Production? There have been new records inserted, and I would prefer to not have to reset the production database, if possible.

I know you guys probably dont care or what to help with this but I got taken down in the support communities because I simply run a beta version (didn’t even discuss it) but here we go **My MacBook Air has multiple accounts and the other users & shared category takes up 100+ gb. When I sign into one of the accounts, that 100+ gb gets moved to System Data. When I look in finder, the user only seems to take up 12 gb, though. I’ve shown hidden items and looked through the library, but it’s not showing anything that’s taking up that much space! **

I am experiencing catastrophic data loss affecting years of documents after a routine iPhone-to-iPhone iCloud synchronization. Standard Apple Support has been unable to resolve this issue, and I urgently need engineering-level assistance. INCIDENT SUMMARY: Date: August 9, 2025 Action: Synced iCloud from iPhone 16 to iPhone 12 mini Result: ALL files in iCloud Drive on Mac disappeared Data lost: Multiple years of documents including critical PDF files Support Case #: 102658156364 TECHNICAL DETAILS: Mac: MacBook Pro running macOS Sonoma 14.6.1 Source: iPhone 16 Destination: iPhone 12 mini iCloud account: info@birth2death. com WHAT HAPPENED: Had fully populated iCloud Drive on Mac and iPhone 16 Signed into iCloud on iPhone 12 mini to sync data After sync completion, Mac's iCloud Drive became completely empty Desktop and Documents folders show in structure but contain no files iCloud.com shows empty folders "Recently Deleted" in iCloud.com is also empty ATTEMPTED RECOVERY: Checked ~/Library/Mobile Documents/ - only folder structure remains Verified with 'brctl dump' - shows folders but no documents Checked all trash locations - empty No Time Machine backup available Apple Support unable to recover server-side backups

Hi. I am having this error when trying to write to CloudKit public database. <CKError 0x600000dbc4e0: "Permission Failure" (10/2007); server message = "Invalid bundle ID for container"; On app launch, I check for account status and ensure that the correct bundle identifier and container is being used. When the account status is checked, I do get the correct bundle id and container id printed in the console but trying to read or write to the container would throw that "Invalid bundle ID for container" error. private init() { container = CKContainer.default() publicDB = container.publicCloudDatabase // Check iCloud account status checkAccountStatus() } func checkAccountStatus() { print("🔍 CloudKit Debug:") print("🔍 Bundle identifier from app: (Bundle.main.bundleIdentifier ?? "unknown")") print("🔍 Container identifier: (container.containerIdentifier ?? "unknown")") container.accountStatus { [weak self] status, error in DispatchQueue.main.async { switch status { case .available: self?.isSignedIn = true self?.fetchUserID() case .noAccount, .restricted, .couldNotDetermine: self?.isSignedIn = false self?.errorMessage = "Please sign in to iCloud in Settings to use this app." default: self?.isSignedIn = false self?.errorMessage = "Unknown iCloud account status." } print("User is signed into iCloud: \(self?.isSignedIn ?? false)") print("Account status: \(status.rawValue)") } } } I have tried: Creating a new container Unselecting and selecting the container in signing & capabilities Unselecting and selecting the container in App ID Configuration I used to have swift data models in my code and read that swift data is not compatible with CloudKit public data so I removed all the models and any swift data codes and only uses CloudKit public database. let savedRecord = try await publicDB.save(record) Nothing seems to work. If anyone could help please? Rgds, Hans

Hello, I'm working on a iOS project, and I added a setup precedure to save and load configuration files during the app's initialization process. However, I can't find my files in my iPhone test while it's Ok on my Mac. How can I retrieve them? Thanks

I have an app which uses key-value storage and will not sync data past a certain size -- meaning that device "A" will send the data to the cloud but device "B" will never receive the updated data. Device "B" will receive the NSUbiquitousKeyValueStoreDidChangeExternallyNotification that the KVS changed but the data is empty. The data in in the KVS is comprised of 4 keys, each containing a value of NSData generated by NSKeyedArchiver. The NSData is comprised of property-list data types (e.g. numbers, strings, dates, etc.) I've verified that the KVS meets the limits of: A total of 1 MB per app, with a per-key limit of 1 MB A per-key value size limit of 1 MB, and a maximum of 1024 keys A maximum length for key strings is 64 bytes using UTF8 encoding Also, the app has never received an NSUbiquitousKeyValueStoreQuotaViolationChange notification. Of the 4 keys, 3 of them contain no more than 30 KB of data each. However, one of the keys can contain as much as 160 KB of data which will not sync to another device. Strangely, if I constrain the data to 100 KB it will work, however, that is not ideal as it is a fraction of the necessary data. I don't see any errors in the debug log either. Any suggestions on what to try next to get this working?

My use case is the following: Every user of my app can create as an owner a set of items.  These items are private until the owner invites other users to share all of them as participant. The participants can modify the shared items and/or add other items. So, sharing is not done related to individual items, but to all items of an owner. I want to use CoreData & CloudKit to have local copies of private and shared items. To my understanding, CoreData & CloudKit puts all mirrored items in a special zone „com.apple.coredata.cloudkit.zone“. So, this zone should be shared, i.e. all items in it. In the video it is said that NSPersistentCloudKitContainer uses Record Zone Sharing optionally in contrast to hierarchically record sharing using a root record. But how is this done? Maybe I can declare zone „com.apple.coredata.cloudkit.zone“ as a shared zone?

I have a DocumentGroup working with a FileDocument, and that's fine. However, when someone creates a new document I want them to have to immediately save it. This is the behavior on ipadOS and iOS from what I can understand (you select where before the file is created). There seems to be no way to do this on macOS? I basically want to have someone: create a new document enter some basic data hit "create" which saves the file then lets the user start editing it (1), (2), and (4) are done and fairly trivial. (3) seems impossible, though...? This really only needs to support macOS but any pointers would be appreciated.

I'm trying to set up server-to-server authentication with CloudKit Web Services, but keep getting AUTHENTICATION_FAILED errors. I've tried multiple environment settings and debugging approaches without success. What I've Tried I created a Swift script to test the connection. Here's the key part that handles the authentication: // Get current ISO 8601 date let iso8601Formatter = ISO8601DateFormatter() iso8601Formatter.formatOptions = [.withInternetDateTime] let dateString = iso8601Formatter.string(from: Date()) // Create SHA-256 hash of request body let bodyHash = SHA256.hash(data: bodyData).compactMap { String(format: "%02x", $0) }.joined() // Get path from URL let path = request.url?.path ?? "/" // String to sign let method = request.httpMethod ?? "POST" let stringToSign = "\(method):\(path):\(dateString):\(bodyHash)" // Sign the string with EC private key let signature = try createSignature(stringToSign: stringToSign) // Add headers request.setValue(dateString, forHTTPHeaderField: "X-Apple-CloudKit-Request-ISO8601Date") request.setValue(KEY_ID, forHTTPHeaderField: "X-Apple-CloudKit-Request-KeyID") request.setValue(signature, forHTTPHeaderField: "X-Apple-CloudKit-Request-SignatureV1") } I've made a request to this endpoint: What's Happening I get a 401 status with this response: "uuid" : "173179e2-c5a5-4393-ab4f-3cec194edd1c", "serverErrorCode" : "AUTHENTICATION_FAILED", "reason" : "Authentication failed" } What I've Verified The key validates correctly and generates signatures The date/time is synchronized with the server The key ID matches what's in CloudKit Dashboard I've tried all three environments: development, Development (capital D), and production The container ID is formatted correctly Debug Information My debugging reveals: The EC key is properly formatted (SEC1 format) Signature generation works No time synchronization issues between client and server All environment tests return the same 401 error Questions Has anyone encountered similar issues with CloudKit server-to-server authentication? Are there specific container permissions needed for server-to-server keys? Could there be an issue with how the private key is formatted or processed? Are there any known issues with the CloudKit Web Services API that might cause this? Any help would be greatly appreciated!

I have an iOS app that downloads HLS files, which are protected by FairPlay. These files are stored locally, and their locations are managed using Core Data. When playing these tracks, I use AVURLAsset to access the stored file paths. Recently, a client upgraded to a new iPhone and used Quick Start to transfer data from his old device. While all other app data was successfully transferred, including Core Data records and UserDefaults, the actual HLS files were missing. As a result, the app retained metadata about the downloaded content, but the files themselves were gone, causing playback failures. Does Quick Start exclude certain types of locally stored files, especially DRM-protected HLS downloads, or is the issue related to how FairPlay-protected content is handled during the transfer of locally stored files?

Problem Description: When a device (Device 2) stays offline for an extended period after a record is deleted from another synced device (Device 1) via CloudKit, is it possible for Device 2 to miss the deletion notification when it reconnects, even when using CKSyncEngine? This scenario raises questions about whether CKSyncEngine can reliably sync changes if CloudKit archives or purges metadata related to deletions during the offline period. Steps to Reproduce: At time t0: · Device 1 and Device 2 sync successfully via CKSyncEngine (shared record RecordA). Device 2 goes offline. On Device 1: · Delete RecordA; sync completes via CKSyncEngine. Wait for a duration potentially exceeding CloudKit’s change retention window (if such a window exists). Bring Device 2 back online. Observe synchronization: · Expected Behavior: CKSyncEngine removes RecordA from Device 2. · Observed Behavior: RecordA remains on Device 2. Key Questions: Under these conditions, can Device 2 permanently miss the deletion event due to CloudKit’s internal metadata management? Is there a documented retention policy for CloudKit’s change history, and how does CKSyncEngine handle scenarios where this history is truncated? What is the recommended pattern to ensure no events are missed, regardless of offline duration? Clarifications Needed: · If CloudKit does discard deletion metadata after a period, is this considered a framework limitation, or should developers implement additional safeguards? · Does CKSyncEngine log warnings or errors when it detects incomplete sync histories? Environment: · CKSyncEngine with SQLite · CloudKit Private Database · iOS/macOS latest versions Thank you for clarifying how CKSyncEngine is designed to handle this edge case!

Dear Apple Developer Support, I hope this message finds you well. I am reaching out for guidance on a project that involves sharing heart rate data between an iOS app and an Android app. I have developed a watchOS app that continuously fetches heart rate data from an Apple Watch and displays it in a companion iOS app. Additionally, I have built an Android fitness app using Ionic Angular. My goal is to create a bridge that allows the heart rate data from the iOS app to be displayed continuously in the Android app. I am considering using a backend server (e.g., Node.js) to facilitate this data transfer. Could you please provide any insights or recommendations on the best approach for achieving this cross-platform data sharing? I would appreciate any guidance on potential challenges or limitations I might encounter. Thank you for your time and assistance. Sincerely, Venu Madhav

Hi everyone, I've recently implemented CKSyncEngine in my app, and I have two questions regarding its behavior: Duplicate FetchedRecordZoneChanges After Sending Changes: I’ve noticed that the engine sometimes receives a FetchedRecordZoneChanges event containing modifications and deletions that were just sent by the same device a few moments earlier. This event arrives after the SentRecordZoneChanges event, and both events share the same recordChangeTag, which results in double-handling the record. Is this expected behavior? I’d like to confirm if this is how CKSyncEngine works or if I might be overlooking something. Handling Initial Sync with a "Sync Screen": When a user opens the app for the first time and already has data stored in iCloud, I need to display a "Sync Screen" temporarily to prevent showing partial data or triggering abrupt, rapid UI changes. I’ve found that canceling current operations, then awaiting sendChanges() and fetchChanges() works well to ensure data is fully synced before dismissing the sync screen: displaySyncScreen = true await syncEngine.cancelOperations() try await syncEngine.sendChanges() try await syncEngine.fetchChanges() displaySyncScreen = false However, I’m unsure if canceling operations like this could lead to data loss or other issues. Is this a safe approach, or would you recommend a better strategy for handling this initial sync state?

I'm working on a cross-platform application that needs to access file attributes, specifically for files and directories in sync drives like OneDrive. On Windows, I use the GetFileInformationByHandle API to retrieve attributes such as FILE_ATTRIBUTE_RECALL_ON_DATA_ACCESS and FILE_ATTRIBUTE_RECALL_ON_OPEN to identify files that are stored remotely or in the cloud. Is there an equivalent API or mechanism on macOS to achieve the same? Specifically, I’m looking for a way to: Identify attributes similar to cloud/offline storage status for files in synced drives (e.g., OneDrive, iCloud Drive). Retrieve metadata to distinguish files/folders stored locally versus those stored remotely and downloaded on access. If there’s a preferred macOS framework (like Core Services or FileManager in Swift) for such operations, examples would be greatly appreciated!

I'm working on a cross-platform application that needs to access file attributes, specifically for files and directories in sync drives like OneDrive. On Windows, I use the GetFileInformationByHandle API to retrieve attributes such as FILE_ATTRIBUTE_RECALL_ON_DATA_ACCESS and FILE_ATTRIBUTE_RECALL_ON_OPEN to identify files that are stored remotely or in the cloud. Is there an equivalent API or mechanism on macOS to achieve the same? Specifically, I’m looking for a way to: Identify attributes similar to cloud/offline storage status for files in synced drives (e.g., OneDrive, DropBox etc). Retrieve metadata to distinguish files/folders stored locally versus those stored remotely and downloaded on access. If there’s a preferred macOS framework (like Core Services or FileManager in Swift) for such operations, examples would be greatly appreciated!