I have a SwiftData application that is using CloudKit. If user is on new device. How can I check and fetch data, instead of just waiting for it happen on its own randomly? For example, I have onboarding which I do not want user to go through again if they already have an active installation. Seems like SwiftData is severely limited in pretty much every way, specially any useful CloudKit debugging or control functionality.

I implemented the cloudkit function, where users can connect with each other. The problem is, that if User A is doing a friend request and User B is accepting the request. The friend entry is correct visible for User B but not for User A. I can see in cloud kit that after the accepted request, the friend connection is set up correctly, also with the correct userID, but it not showing up for User A (the one that send the request)

if it set com.apple.CoreData.ConcurrencyDebug 1 as launch arg the app always crashes and i cant proceed into the app. is there a way to only raise a warning for these issues so that i can go into the app and check every place in one session for coredata errors?

Hi everyone, I’m currently developing a SwiftUI app that uses SwiftData with CloudKit sharing enabled. The app works fine on my own Apple ID, and local syncing with iCloud is functioning correctly — but sharing with other Apple IDs consistently fails. Setup: SwiftUI + SwiftData using a ModelContainer with .shared configuration Sharing UI is handled via UICloudSharingController iCloud container: iCloud.com.de.SkerskiDev.FoodGuard Proper entitlements enabled (com.apple.developer.icloud-services, CloudKit, com.apple.developer.coredata.cloudkit.containers, etc.) Automatic provisioning profiles created by Xcode Error:<CKError 0x1143a2be0: "Bad Container" (5/1014); "Couldn't get container configuration from the server for container iCloud.com.de.SkerskiDev.FoodGuard"> What I’ve tried: Verified the iCloud container is correctly created and enabled in the Apple Developer portal Checked bundle identifier and container settings Rebuilt and reinstalled the app Ensured correct iCloud entitlements and signing capabilities Questions: Why does CloudKit reject the container for sharing while local syncing works fine? Are there known issues with SwiftData .shared containers and multi-user sharing? Are additional steps required (App Store Connect, privacy settings) to allow sharing with other Apple IDs? Any advice, experience, or example projects would be greatly appreciated. 🙏 Thanks! Sebastian

When I tried to use a working project with iOS 18 installed on my device, it wouldn't work anymore and crash right away. Before with iOS 17 it was working fine. I can't access child variables that are saved in an Array in a parent object in SwiftData. The error is always somewhere in these hidden lines: { @storageRestrictions(accesses: _$backingData, initializes: _title) init(initialValue) { _$backingData.setValue(forKey: \.title, to: initialValue) _title = _SwiftDataNoType() } get { _$observationRegistrar.access(self, keyPath: \.title) return self.getValue(forKey: \.title) } set { _$observationRegistrar.withMutation(of: self, keyPath: \.title) { self.setValue(forKey: \.title, to: newValue) } } } The child classes are also inserted and saved into the modelContext when created and set to the parent instance, but I also can't fetch them via modelContext.fetch() - Error here is: Thread 1: EXC_BREAKPOINT (code=1, subcode=0x243a62a4c) Maybe there is a problem with the relationship between two saved instances. The parent instances are saved correctly and it was working in iOS 17. The problem is similar to these two cases: https://forums.developer.apple.com/forums/thread/762679 https://forums.developer.apple.com/forums/thread/738983 I changed the logic after I reviewed these threads, as I am now linking the parent and child instances, that got rid of one warning in the console. button.canvas = canvas modelContext.insert(button) canvas.buttons = [button] But in the end those threads were not enough for me to find a fix for my problem. A small project can be found here: https://github.com/DonMalte/SwiftDataTest

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?

I am using cloudkit to save users high scores in a public database. The preference over using Game Center is because of simplicity and works really well for what I want to achieve. I simply want to let users know their global position. Because of data privacy laws the app asks the user for their permission to submit their score each time they get a new high score. However, I have noticed that CKRecords under 'created' and 'modified' in addition to UTC time and date also contain creatorUserRecordID. Could this be a privacy issue? Can you extract any personal information from this? Can this be used to track back to the user? Is it linked to CKUserIdentity which I understand does contain personal information, although as I understand you need users consent to get this information. Under creatorUserRecordID it says... "Every user of the app has a unique user record that is empty by default. Apps can add data to the user record on behalf of the user, but don’t store sensitive data in it" Currently I simply ask the user if they are happy to submit their score. But do I need to point out that it also stores a creatorUserRecordID? Obviously I don't want to do this if it is not needed as the user will 1) Probably not understand what a creatorUserRecordID is and 2) It makes the question complicated and will likely make most people refuse to submit their score. If it is a privacy issue, is there anyway to stop a CKRecord creating this ID and simply save a score? All I need is a list of scores so the app can determine their current position. If creatorUserRecordID does not contain any personal details and cannot be tracked back to the user please let me know, so I can be reassured that my current set up is fine and I am not causing any privacy issues! This post did seem to indicate you may possibly be able to fetch personal details?? https://stackoverflow.com/questions/55782166/how-do-i-fetch-any-info-about-user-that-modified-ckrecord

While experimenting with CloudKit dashboard, I accidentally turned off a iCloud container. Now in the Certificates, Identifiers & Profiles section of developer portal, this iCloud container identifier is listed under "hidden" not "active" I can edit its name but there is not way to unhide or active it again. What am I missing?

Hello ! I am using this iCloud key value pair mechanism to save small app configuration between iOS and tvOS. I would say it is working. But when I go back and forth between debug and release (TestFlight) modes, it is like both apps are not connected anymore. I spend a lot of time restarting all devices, rebuilding, activating / deactivating iCloud capabilities in the Xcode project. It is like the app is mixing debug and release data. Is there an easy way to check what is happening exactly ? I know there's nothing on CloudKit console, so .... Thank you Frederic

Is it possible to track history using the new HistoryDescriptor feature in SwiftData? Or can I only get the current most recent data? Or is it possible to output the changed data itself, along with timestamps? I am hoping that it is possible to track by a standard feature like NSPersistentHistoryTransaction in CoreData. Do we still have to use a method in SwiftData that creates more tracking data itself?

Hi everyone! I have an app on the App Store that uses Core Data as its data store. (It's called Count on Me: Tally Counter. Feel free to check it out.) One of the app's core feature is an interactive widget with a simple button. When the button is tapped, it's supposed to update the entity in the store. My requirement is that the changes are then reflected with minimal latency in the main app and – ideally – also on other devices of the same iCloud user. And vice-versa: When an entity is updated in the app (or on another device where the same iCloud user is logged in), the widget that shows this entity should also refresh to reflect the changes. I have read multiple articles, downloaded sample projects, searched Stackoverflow and the Apple developer forums, and tried to squeeze a solution out of AI, but couldn't figure out how to make this work reliably. So I tried to reduce the core problem to a minimal example project. It has two issues that I cannot resolve: When I update an entity in the app, the widget is immediately updated as intended (due to a call to WidgetCenter's reloadAllTimelines method). However, when I update the same entity from the interactive widget using the same app intent, the changes are not reflected in the main app. For the widget and the app to use the same local data store, I need to enable App Groups in both targets and set a custom location for the store within the shared app group. So I specify a custom URL for the NSPersistentStoreDescription when setting up the Core Data stack. The moment I do this, iCloud sync breaks. Issue no. 1 is far more important to me as I haven't officially enabled iCloud sync yet in my real app that's already on the App Store. But it would be wonderful to resolve issue no. 2 as well. Surely, there must be a way to synchronize changes to the source of truth triggered by interactive widget with other devices of the same iCloud user. Otherwise, the feature to talk to the main app and the feature to synchronize with iCloud would be mutually exclusive. Some other developers I talked to have suggested that the widget should only communicate proposed changes to the main app and once the main app is opened, it processes these changes and writes them to the NSPersistentCloudKitContainer which then synchronizes across devices. This is not an option for me as it would result in a stale state and potential data conflicts with different devices. For example, when a user has the same widget on their iPhone and their iPad, taps a button on the iPhone widget, that change would not be reflected on the iPad widget until the user decides to open the app on the iPhone. At the same time, the user could tap the button multiple times on their iPad widget, resulting in a conflicting state on both devices. Thus, this approach is not a viable solution. An answer to this question will be greatly appreciated. The whole code including the setup of the Core Data stack is included in the repository reference above. Thank you!

I have an app which uses ubiquitous containers and files in them to share data between devices. It's a bit unusual in that it indexes files in directories the user grants access to, which may or may not exist on a second device - those files are identified by SHA-1 hash. So a second device scanning before iCloud data has fully sync'd can create duplicate references which lead to an unpleasant user experience. To solve this, I store a small binary index in the root of the ubiquitous file container of the shared data, containing all of the known hashes, and as the user proceeds through the onboarding process, a background thread is attempting to "prime" the ubiquitous container by calling FileManager.default.startDownloadingUbiquitousItemAt() for each expected folder and file in a sane order. This likely creates a situation not anticipated by the iOS/iCloud integration's design, as it means my app has a sort of precognition of files it should not yet know about. In the common case, it works, but there is a corner case where iCloud sync has just begun, and very, very little metadata is available (the common case, however, in an emulator), in which two issues come up: I/O may hang indefinitely, trying to read a file as it is arriving. This one I can work around by running the I/O in a thread created with the POSIX pthread_create and using pthread_cancel to kill it after a timeout. Attempts to call FileManager.default.startDownloadingUbiquitousItemAt() fails with an error Error Domain=NSCocoaErrorDomain Code=257 "The file couldn’t be opened because you don’t have permission to view it.". The permissions aspect of it is nonsense, but I can believe there's no applicable "sort of exists, sort of doesn't" error code to use and someone punted. The problem is that this same error will be thrown on any attempt to access that file for the life of the application - a restart is required to make it usable. Clearly, the error or the hallucinated permission failure is cached somewhere in the bowels of iOS's FileManager. I was hoping startAccessingSecurityScopedResource() would allow me to bypass such a cache, as it does with URL.resourceValues() returning stale file sizes and last modified times. But it does not. Is there some way to clear this state without popping up a UI with an Exit button (not exactly the desired iOS user experience)?

I get the following fatal error when the user clicks Save in AddProductionView. Fatal error: Duplicate keys of type 'AnyHashable' were found in a Dictionary. This usually means either that the type violates Hashable's requirements, or that members of such a dictionary were mutated after insertion. As far as I’m aware, SwiftData automatically makes its models conform to Hashable, so this shouldn’t be a problem. I think it has something to do with the picker, but for the life of me I can’t see what. This error occurs about 75% of the time when Save is clicked. I'm using Xcode 16.2 and iPhone SE 2nd Gen. Any help would be greatly appreciated… Here is my code: import SwiftUI import SwiftData @main struct MyApp: App { var body: some Scene { WindowGroup { ContentView() .modelContainer(for: Character.self, isAutosaveEnabled: false) } } } @Model final class Character { var name: String var production: Production var myCharacter: Bool init(name: String, production: Production, myCharacter: Bool = false) { self.name = name self.production = production self.myCharacter = myCharacter } } @Model final class Production { var name: String init(name: String) { self.name = name } } struct ContentView: View { @State private var showingSheet = false var body: some View { Button("Add", systemImage: "plus") { showingSheet.toggle() } .sheet(isPresented: $showingSheet) { AddProductionView() } } } struct AddProductionView: View { @Environment(\.dismiss) private var dismiss @Environment(\.modelContext) var modelContext @State var production = Production(name: "") @Query var characters: [Character] @State private var characterName: String = "" @State private var selectedCharacter: Character? var filteredCharacters: [Character] { characters.filter { $0.production == production } } var body: some View { NavigationStack { Form { Section("Details") { TextField("Title", text: $production.name) } Section("Characters") { List(filteredCharacters) { character in Text(character.name) } HStack { TextField("Character", text: $characterName) Button("Add") { let newCharacter = Character(name: characterName, production: production) modelContext.insert(newCharacter) characterName = "" } .disabled(characterName.isEmpty) } if !filteredCharacters.isEmpty { Picker("Select your role", selection: $selectedCharacter) { Text("Select") .tag(nil as Character?) ForEach(filteredCharacters) { character in Text(character.name) .tag(character as Character?) } } .pickerStyle(.menu) } } } .toolbar { Button("Save") { //Fatal error: Duplicate keys of type 'AnyHashable' were found in a Dictionary. This usually means either that the type violates Hashable's requirements, or that members of such a dictionary were mutated after insertion. if let selectedCharacter = selectedCharacter { selectedCharacter.myCharacter = true } modelContext.insert(production) do { try modelContext.save() } catch { print("Failed to save context: \(error)") } dismiss() } .disabled(production.name.isEmpty || selectedCharacter == nil) } } } }

It takes a few seconds, sometimes a few minutes for records to be downloaded back from CloudKit when the user reinstalls the app, which leads users to thinking their data was lost. I would like to know if there’s any way to provide a visual feedback about the current CloudKit sync status so I can let users know their data is being in fact downloaded back to their devices.

In Apple Numbers and similar apps, a user can save a document to iCloud Drive, and collaborate with other users. From what I can gather, it seems to use two mechanisms: the document as a whole is synced via iCloud Drive, but when a collaboration is started, it seems to use CloudKit records to do live updates. I am working on a similar app, that saves documents to iCloud Drive (on Mac, iPad, and iPhone). Currently it only syncs via iCloud Drive, re-reading the entire (often large) document when a remote change occurs. This can lead to a delay of several seconds (up to a minute) for the document to be saved, synced to the server, synced from the server, and re-read. I'm working on adding a "live sync", i.e. the ability to see changes in as near to real-time as feasible, like in Apple's apps. The document as a whole will remain syncing via iCloud Drive. My thought is to add a CloudKit CKRecord-based sync when two or more users are collaborating on a document, recording only the diffs for quick updates. The app would no longer re-read the entire document when iCloud Drive updates it while in use, and would instead read the CloudKit records and apply those changes. This should be much faster. Is my understanding of how Apple does it correct? Does my proposed approach seem sensible? Has anyone else implemented something like this, with iCloud Drive-based documents and a CloudKit live sync? In terms of technologies, I see that Apple now has a Shared with You framework, with the ability to use a NSItemProvider to start the collaboration. Which raises the question, should I use the iCloud Drive document for the collaboration (as I do now), or the CloudKit CKShare diff? I think I'd have to use the document as a whole, both so it works with the Send Copy option, and so a user that doesn't have the document gets it when using Collaborate. Once the collaboration is underway, I'd want to start the CloudKit channel. So I guess I'd save the CKShare to the server, get its URL, and save that in the document, so another user can read that URL as part of their initial load of the document from iCloud Drive? Once two (or more) users have the document via iCloud Drive, and the CKShare via the embedded URL, I should be able to do further live-sync updates via CloudKit. If a user closes the document and re-opens it, they'd get the updates via iCloud Drive, so no need to apply any updates from before the document was opened. Does all this sound reasonable, or am I overlooking some gotcha? I'd appreciate any advice from people who have experience with this kind of syncing.

Hey guys, I'm developing a Swift app, using iCloud to store some data in Containers, and the new Containers I created are iCloud.com.xxx.dev . Therefore, there is a storage called dev in Settings -> icloud -> Manage Account Storage. Currently, the app is still under development and has not been released to the Appstore. My question: Settings -> icloud -> Manage Account Storage does not display my app name and icon, but only the suffix of the Containers id. Will this change after it is released to the Appstore? Are there any other control methods? Thank you

Is there a way to move user data from UserDefaults to SwiftData when the app is in production so that people don’t lose their data. Currently my audio journals in my journal app has everything in the UserDefaults. Now this is bad for obvious reasons but I was thinking if there was a way. It’s only been 1 week since published and I have already had17 people download it.

Hi Developer Community, I'm experiencing a critical issue with CloudKit schema deployment that's blocking my app release. I've been trying to resolve this for several days and would appreciate any assistance from the community or Apple engineers. Issue Description I'm unable to deploy my CloudKit schema from development to production environment. When attempting to deploy through the CloudKit Dashboard, I either get an "Internal Error" message or the deployment button is disabled. Environment Details App: Reef Trak (Reef aquarium tracking app) CloudKit Container: ************ Development Environment: Schema fully defined and working correctly Production Environment: No schema deployed (confirmed in dashboard) What I've Tried Using the "Deploy Schema to Production" button in CloudKit Dashboard (results in "Internal Error") Exporting schema from development and importing to production (fails) Using CloudKit CLI tools with API token (results in "invalid-scope" errors) Waiting 24-48 hours between attempts in case of propagation delays Current Status App works perfectly in development environment (when run from Xcode) In TestFlight/sideloaded builds (production environment), the app attempts to fetch records but fails with "Did not find record type: Tank" errors Log snippet showing the issue: [2025-03-21] [CloudKit] Schema creation failed: Error saving record <CKRecordID: 0x******; recordName=SchemaSetup_Tank_-**---****, zoneID=_defaultZone:defaultOwner> to server: Cannot create new type Tank in production schema [2025-03-21] [CloudKit] Failed to create schema for Tank after 3 attempts [2025-03-21] [CloudKit] Error creating schema for Tank: Error saving record <CKRecordID: 0x****; recordName=SchemaSetup_Tank_---**-**********, zoneID=_defaultZone:defaultOwner> to server: Cannot create new type Tank in production schema App Architecture & Critical Impact My app "Reef Trak" is built around a core data model where the "Tank" entity serves as the foundational element of the entire application architecture. The Tank entity is not just another data type - it's the primary container that establishes the hierarchical relationship for all other entities: All parameter measurements (pH, temperature, salinity, etc.) are associated with specific tanks All maintenance tasks and schedules are tank-specific All livestock (fish, corals, invertebrates) exist within the context of a tank All user achievements and progress tracking depend on tank-related activities Without the Tank schema being properly deployed to production, users experience what appears to be a completely empty application, despite successful authentication and CloudKit connection. The app shows "Successfully retrieved iCloud data" but displays no content because: The Tank record type doesn't exist in production Without Tanks, all child entities (even if their schemas existed) have no parent to associate with This creates a cascading failure where no data can be displayed or saved This issue effectively renders the entire application non-functional in production, despite working flawlessly in development. Users are left with an empty shell of an app that cannot fulfill its core purpose of reef tank management and monitoring. The inability to deploy the Tank schema to production is therefore not just a minor inconvenience but a complete blocker for the app's release and functionality. Questions Is there an alternative method to deploy schema to production that I'm missing? Could there be an issue with my account permissions or container configuration? Are there known issues with the CloudKit Dashboard deployment functionality? What's the recommended approach when the dashboard deployment fails? I've also submitted a Technical Support Incident, but I'm hoping to get this resolved quickly as it's blocking my App Store release. Thank you for any assistance!

I have been trying to get this to work since it was announced a few years ago but with no joy. I'm struggling to get Apple's example code to behave itself too. Seems overly complex and buggy. So I set out to create a simplified version myself. I have got the database to sync with CloudKit and I can see my records in the developer dashboard. I'm trying to use container.record(for: object.objectID) to get the CKRecord for it, but this always fails. The next step would be to add the participant. I try to add the participant based on this code: Button { let record = fetchRecord(for: items[0]) //hack just to use the first record for dev testing let share = CKShare(rootRecord: record) let persistenceController = PersistenceController.shared persistenceController.addParticipant( emailAddress: "andrew@ambrit.com", permission: .readWrite, share: share) { share, error in if let error = error { print("Error: \(error.localizedDescription)") } else if let share = share { print("Share updated successfully: \(share)") } } } label: { Label("Participants", systemImage: "person") } and extension PersistenceController { func addParticipant(emailAddress: String, permission: CKShare.ParticipantPermission = .readWrite, share: CKShare, completionHandler: ((_ share: CKShare?, _ error: Error?) -> Void)?) { let container = PersistenceController.shared.container let lookupInfo = CKUserIdentity.LookupInfo(emailAddress: emailAddress) let persistentStore = privatePersistentStore //share.persistentStore! container.fetchParticipants(matching: [lookupInfo], into: persistentStore) { (results, error) in guard let participants = results, let participant = participants.first, error == nil else { completionHandler?(share, error) return } participant.permission = permission participant.role = .privateUser share.addParticipant(participant) container.persistUpdatedShare(share, in: persistentStore) { (share, error) in if let error = error { print("\(#function): Failed to persist updated share: \(error)") } completionHandler?(share, error) } } } } My immediate problem is that when I call fetchRecord it doesn't find anything despite the record being available in the CloudKit dashboard. func fetchRecord(for object: NSManagedObject) -> CKRecord { let container = PersistenceController.shared.container print ("Fetching record \(object.objectID)") if let record = container.record(for: object.objectID) { print("CKRecord ID: \(record.recordID)") print("Record Name: \(record.recordID.recordName)") return record } else { fatalError("Record not found") } }

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!