I have been using the basic NSPersistentContainer with 100k+ records for a while now with no issues. The database size can fluctuate a bit but on average it takes up about 22mb on device. When I switch the container to NSPersistentCloudKitContainer, I see a massive increase in size to ~150mb initially. As the sync engine uploads records to iCloud it has ballooned to over 600mb on device. On top of that, the user's iCloud usage in settings reports that it takes up 1.7gb in the cloud. I understand new tables are added and history tracking is enabled but the size increase seems a bit drastic. I'm not sure how we got from 22mb to 1.7gb with the exact same data. A few other things that are important to note: I import all the 100k+ records at once when testing the different containers. At the time of the initial import there is only 1 relation (an import group record) that all the records are attached to. I save the background context only once after all the records and the import group have been made and added to the context. After the initial import, some of these records may have a few new relations added to them over time. I suppose this could be causing some of the size increase, but its only about 20,000 records that are updated. None of the records include files/ large binary data. Most of the attributes are encrypted. I'm syncing to the dev iCloud environment. When I do make a change to a single attribute in a record, CloudKit reports that every attribute has been modified (not sure if this is normal or not ) Also, When syncing to a new device, the sync can take hours - days. I'm guessing it's having to sync both the new records and the changes, but it exponentially gets slower as more records are downloaded. The console will show syncing activity, but new records are being added at a slower rate as more records are added. After about 50k records, it grinds to a halt and while the console still shows sync activity, only about 100 records are added every hour. All this to say i'm very confused where these issues are coming from. I'm sure its a combination of how i've setup my code and the vast record count, record history, etc. If anyone has any ideas it would be much appreciated.

it seems that is going to the appstore to find the app to execute the share but my app is not in the appstore yet. I am using a sandboxed user and a non sandboxed user, I have tried real phones connected to xcode and simulator same effect, looking for how to test my ckshare in testflight thanks

Apple WTF? What did you do to all my Apps? none of them work in iOS26.1 (all worked in 26.0). XCode simply says: CoreData: error: addPersistentStoreWithType:configuration:URL:options:error: returned error NSCocoaErrorDomain (134140) * SwiftData is supposed to do all these automatically 🤷🏻

I see a chunk load error in the browser console. I already reported this: FB17664487

If I have two consecutive calls like to perform(schedule: .immediate) like so: func doSomething() async { await self.perform(schedule: .immediate) { // add log event 1 to data store } await self.perform(schedule: .immediate) { // add log event 2 to data store } } Can I be guaranteed that the block for log event 1 will happen after log event 2? "log event" here is just an example, so please ignore things like storing date, etc. Looking at the documentation here: https://developer.apple.com/documentation/coredata/nsmanagedobjectcontext/perform(schedule:_:) It's a little unclear whether any such guarantee is in place. However, given that the function returns the value from the block, it seems like I should be able to expect event 1 will always be executed before event 2 regardless of the schedule parameter?

I am using SwiftData with CloudKit to synchronize data across multiple devices, and I have encountered an issue: occasionally, abnormal sync behavior occurs between two devices (it does not happen 100% of the time—only some users have reported this problem). It seems as if synchronization between the two devices completely stops; no matter what operations are performed on one end, the other end shows no response. After investigating, I suspect the issue might be caused by both devices simultaneously modifying the same field, which could lead to CloudKit's logic being unable to handle such conflicts and causing the sync to stall. Are there any methods to avoid or resolve this situation? Of course, I’m not entirely sure if this is the root cause. Has anyone encountered a similar issue?

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.

CloudKit CKRecordZone Deletion Issue Problem: CloudKit record zones deleted via CKDatabase.modifyRecordZones(deleting:) or CKModifyRecordZonesOperation are successfully removed but then reappear. I suspect they are automatically reinstated by CloudKit sync, despite successful deletion confirmation. Environment: SwiftData with CloudKit integration Custom CloudKit zones created for legacy zone-based sharing Observed Behavior: Create custom zone (e.g., "TestZone1") via CKDatabase.modifyRecordZones(saving:) Copy records to zone for sharing purposes Delete zone using any CloudKit deletion API - returns success, no errors Immediate verification: Zone is gone from database.allRecordZones() After SwiftData/CloudKit sync or app restart: Zone reappears Reproduction: Tested with three different deletion methods - all exhibit same behaviour: modifyRecordZones(deleting:) async API CKModifyRecordZonesOperation (fire-and-forget) CKModifyRecordZonesOperation with result callbacks Zone deletion succeeds, change tokens (used to track updates to shared records) cleaned up But zones are restored presumably by CloudKit background sync Expected: Deleted zones should remain deleted Actual: Zones are reinstated, creating orphaned zones

Hello Devs, I'm encountering a persistent INTERNAL_ERROR (HTTP 500) when making Server-to-Server API calls to CloudKit, specifically when trying to hit the /users/current endpoint, even after meticulously verifying all client-side components. I'm hoping someone might have insight into what could cause this. Context: Goal: Authenticate to CloudKit from a Vercel Serverless Function (Node.js) to perform operations like record queries. Problem Endpoint: POST https://api.apple-cloudkit.com/database/1/iCloud.com.dannybaseball.Danny-Baseball/production/public/users/current Key Generation Method: Using the CloudKit Dashboard's "Tokens & Keys" -> "New Server-to-Server Key" flow, where I generate the private key using openssl ecparam -name prime256v1 -genkey -noout -out mykey.pem, then extract the public key using openssl ec -in mykey.pem -pubout, and paste the public key material (between BEGIN/END markers) into the dashboard. The private key was then converted to PKCS#8 format using openssl pkcs8 -topk8 -nocrypt -in mykey.pem -out mykey_pkcs8.pem. Current Setup Being Tested (in a Vercel Node.js function): CLOUDKIT_CONTAINER: iCloud.com.dannybaseball.Danny-Baseball CLOUDKIT_KEY_ID: 9368dddf141ce9bc0da743b9f69bc3eda132b9bb3e62a4167e428d4f320b656e (This is the Key ID generated from the CloudKit Dashboard for the public key I provided). CLOUDKIT_P8_KEY (Environment Variable): Contains the base64 encoded string of the entire content of my PKCS#8 formatted private key file. Key Processing in Code: const p8Base64 = process.env.CLOUDKIT_P8_KEY; const privateKeyPEM = Buffer.from(p8Base64, 'base64').toString('utf8'); // This privateKeyPEM string starts with "-----BEGIN PRIVATE KEY-----" and ends with "-----END PRIVATE KEY-----" const privateKey = crypto.createPrivateKey({ key: privateKeyPEM, format: 'pem' }); // This line SUCCEEDS without DECODER errors in my Vercel function logs. Use code with caution. JavaScript Request Body for /users/current: "{}" Signing String (message = Date:BodyHash:Path): Date: Correct ISO8601 format (e.g., "2025-05-21T19:38:11.886Z") BodyHash: Correct SHA256 hash of "{}", then Base64 encoded (e.g., "RBNvo1WzZ4oRRq0W9+hknpT7T8If536DEMBg9hyq/4o=") Path: Exactly /database/1/iCloud.com.dannybaseball.Danny-Baseball/production/public/users/current Headers: X-Apple-CloudKit-Request-KeyID: Set to the correct Key ID. X-Apple-CloudKit-Request-ISO8601Date: Set to the date used in the signature. X-Apple-CloudKit-Request-SignatureV1: Set to the generated signature. X-Apple-CloudKit-Environment: "production" Content-Type: "application/json" Observed Behavior & Logs: The Node.js crypto.createPrivateKey call successfully parses the decoded PEM key in my Vercel function. The request is sent to CloudKit. CloudKit responds with HTTP 500 and the following JSON body (UUID varies per request): { "uuid": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", "serverErrorCode": "INTERNAL_ERROR" } Use code with caution. Json This happens consistently. Previously, with other key pairs or different P8 processing attempts, I was getting AUTHENTICATION_FAILED (401) or local DECODER errors. Now that the key parsing is successful on my end with this current key pair and setup, I'm hitting this INTERNAL_ERROR. Troubleshooting Done: Verified Key ID (9368dddf...) is correct and corresponds to the key generated via CloudKit Dashboard. Verified Container ID (iCloud.com.dannybaseball.Danny-Baseball) is correct. Successfully parsed the private key from the environment variable (after base64 decoding) within the Vercel function. Meticulously checked the signing string components (Date, BodyHash, Path) against Apple's documentation. Path format is /database/1////. Ensured all required headers are present with correct values. Local Node.js tests (bypassing Vercel but using the same key data and signing logic) also result in this INTERNAL_ERROR. Question: What could cause CloudKit to return an INTERNAL_ERROR (500) for a /users/current request when the client-side key parsing is successful and all request components (path, body hash for signature, date, headers) appear to conform exactly to the Server-to-Server Web Services Reference? Are there any known subtle issues with EC keys generated via openssl ecparam (and then converted to PKCS#8) that might lead to this, even if crypto.createPrivateKey parses them in Node.js? Could there be an issue with my specific Key ID or container that would manifest this way, requiring Apple intervention? Any insights or suggestions would be greatly appreciated. I can provide more detailed logs of the request components if needed. Thank you!

Hello, In my iOS/SwiftUI/SwiftData app, I want the user to be able to hit [Cancel] from editing in a detail screen and return to the previous screen without changes being saved. I believed that setting autosaveEnabled to false and/or calling .rollback would prevent changes from being saved, unless/until I call .save() when the user clicks [Save], but this does not seem to be correct. I set modelContext.autosaveEnabled = false and I call modelContext.rollback() when the user hits [Cancel], but any changes they made are not rolled back, but saved even if I don’t call save(). I have tried setting autosaveEnabled to false when I create the ModelContainer on a @MainActor function when the App starts, and in the detail/edit screen’s .onAppear(). I can see that .rollback is being called when the [Cancel] button is tapped. In all cases, any changes the user made before hitting [Cancel] are saved. The Developer Documentation on autosaveEnabled includes this: “The default value is false. SwiftData automatically sets this property to true for the model container’s mainContext." I am working on the mainContext, but it appears that setting autosaveEnabled to false has no effect no matter where in the code I set it. If someone sees what I am doing wrong, I’d sure appreciate the input. If this description doesn’t explain the problem well enough, I’ll develop a minimal focused example.

I'm seeing a lot of these in my logs: PersistentIdentifier PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(url: x-swiftdata://Course/BC9CF99A-DE6A-46F1-A18D-8034255A56D8), implementation: SwiftData.PersistentIdentifierImplementation) was remapped to a temporary identifier during save: PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(url: x-coredata:///Course/t58C849CD-D895-4773-BF53-3F63CF48935B210), implementation: SwiftData.PersistentIdentifierImplementation). This is a fatal logic error in DefaultStore ... though everything seems to work. Does anyone know what this means in this context? Anything I can do to not have this appear?

Problem The following code doesn't work: let predicate = #Predicate<Car> { car in car.size == size //This doesn't work } Console Error Query encountered an error: SwiftData.SwiftDataError(_error: SwiftData.SwiftDataError._Error.unsupportedPredicate) Root cause Size is an enum, #Predicate works with other type such as String however doesn't work with enum Enum value is saved however is not filtered by #Predicate Environment Xcode: 15.0 (15A240d) - App Store macOS: 14.0 (23A339) - Release Candidate Steps to reproduce Run the app on iOS 17 or macOS Sonoma Press the Add button Notice that the list remains empty Expected behaviour List should show the newly created small car Actual behaviour List remains empty inspite of successfully creating the small car. Feedback FB13194334 Code Size enum Size: String, Codable { case small case medium case large } Car import SwiftData @Model class Car { let id: UUID let name: String let size: Size init( id: UUID, name: String, size: Size ) { self.id = id self.name = name self.size = size } } ContentView struct ContentView: View { var body: some View { NavigationStack { CarList(size: .small) } } CarList import SwiftUI import SwiftData struct CarList: View { let size: Size @Environment(\.modelContext) private var modelContext @Query private var cars: [Car] init(size: Size) { self.size = size let predicate = #Predicate<Car> { car in car.size == size //This doesn't work } _cars = Query(filter: predicate, sort: \.name) } var body: some View { List(cars) { car in VStack(alignment: .leading) { Text(car.name) Text("\(car.size.rawValue)") Text(car.id.uuidString) .font(.footnote) } } .toolbar { Button("Add") { createCar() } } } private func createCar() { let name = "aaa" let car = Car( id: UUID(), name: name, size: size ) modelContext.insert(car) } }

Hi, I was testing the new iOS 18 behavior where NSPersistentCloudKitContainer wipes the local Core Data store if the user logs out of iCloud, for privacy purposes. I ran the tests both with a Core Data + CloudKit app, and a simple one using SwiftData with CloudKit enabled. Results were identical in either case. In my testing, most of the time, the feature worked as expected. When I disabled iCloud for my app, the data was wiped (consistent with say the Notes app, except if you disable iCloud it warns you that it'll remove those notes). When I re-enabled iCloud, the data appeared. (all done through the Settings app) However, in scenarios when NSPersistentCloudKitContainer cannot immediately sync -- say due to rate throttling -- and one disables iCloud in Settings, this wipes the local data store and ultimately results in data loss. This occurs even if the changes to the managed objects are saved (to the local store) -- it's simply they aren't synced in time. It can be a little hard to reproduce the issue, especially since when you exit to the home screen from the app, it generally triggers a sync. To avoid this, I swiped up to the screen where you can choose which apps to close, and immediately closed mine. Then, you can disable iCloud, and run the app again (with a debugger is helpful). I once saw a message with something along the lines of export failed (for my record that wasn't synced), and unfortunately it was deleted (and never synced). Perhaps before NSPersistentCloudKitContainer wipes the local store it ought to force sync with the cloud first?

I am a novice developer, so please be kind. 😬 I am developing a simple macOS app backed with SwiftData and trying to set up iCloud sync so data syncs between two Macs running the app. I have added the iCloud capability, checked the CloudKit box, and selected an iCloud Container. Per suggestion of Paul Hudson, my model properties have either default values or are marked as optional, and the only relationship in my model is marked as optional. @Model final class Project { // Stable identifier used for restoring selected project across launches. var uuid: UUID? var name: String = "" var active: Bool = true var created: Date = Foundation.Date(timeIntervalSince1970: 0) var modified: Date = Foundation.Date(timeIntervalSince1970: 0) // CloudKit requires to-many relationships to be optional in this schema. @Relationship var timeEntries: [TimeEntry]? init(name: String, active: Bool = true, uuid: UUID? = UUID()) { self.uuid = uuid self.name = name self.active = active self.created = .now self.modified = .now self.timeEntries = [] } @Model final class TimeEntry { // Core timing fields. var start: Date = Foundation.Date(timeIntervalSince1970: 0) var end: Date = Foundation.Date(timeIntervalSince1970: 0) var codeRawValue: String? var activitiesRawValue: String = "" // Inverse relationship back to the owning project. @Relationship(inverse: \Project.timeEntries) var project: Project? init( start: Date = .now, end: Date = .now.addingTimeInterval(60 * 60), code: BillingCode? = nil, activities: [ActivityType] = [] ) { self.start = start self.end = end self.codeRawValue = code?.rawValue self.activitiesRawValue = Self.serializeActivities(activities) } I have set up the following in the AppDelegate for registering for remote notifications as well as some logging to console that the remote notification token was received and to be notified when when I am receiving remote notifications. private final class TimeTrackerAppDelegate: NSObject, NSApplicationDelegate { func applicationDidFinishLaunching(_ notification: Notification) { print("📡 [Push] Registering for remote notifications") NSApplication.shared.registerForRemoteNotifications() } func application(_ application: NSApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) { let tokenPreview = deviceToken.map { String(format: "%02x", $0) }.joined().prefix(16) print("✅ [Push] Registered for remote notifications (token prefix: \(tokenPreview)...)") } func application(_ application: NSApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) { let nsError = error as NSError print("❌ [Push] Failed to register for remote notifications: \(nsError.domain) (\(nsError.code)) \(nsError.localizedDescription)") } func application(_ application: NSApplication, didReceiveRemoteNotification userInfo: [String: Any]) { print("📬 [Push] Received remote notification: \(userInfo)") } } In testing, I run the same commit from Xcode on two different Macs logged into the same iCloud account. My problem is that sync is not reliably working. Starting up the app on both Macs shows that the app successfully registered for remote notifications. Sometimes, making an edit on Mac 1 is immediately reflected in Mac 2 UI along with didReceiveRemoteNotification message (all occurring while the Mac 2 app remains in foreground). Sometimes, the Mac 2 app needs to be backgrounded and re-foregrounded before the UI shows the updated data. Sometimes, an edit on Mac 2 will show on Mac 1 only after re-foregrounded but not show any didReceiveRemoteNotification on the Mac 1 console. Sometimes, an edit on Mac 2 will not show at all on Mac 1 even after re-foregrounding the app. Sometimes, no edits sync between either Mac. I had read about how a few years back, there was a bug in macOS where testing iCloud sync between Macs did not work while running from Xcode but would work in TestFlight. For me, running my app in TestFlight on both Macs has never been able to sync any edits between the Macs. Any idea where I might be going wrong. It seems this should not be this hard and should not be failing so inconsistently. Wondering what I might be doing wrong here.

My iOS app uses CloudKit key-value storage. I have not updated the app in a few years but it works fine. Since it was last updated, I transferred the app from an old organization to my personal developer account. Now that I'm working on the app again I get an error: Provisioning profile "iOS Team Provisioning Profile: com.company.app" doesn't match the entitlements file's value for the com.apple.developer.ubiquity-kvstore-identifier entitlement. In the entitlement file, it has $(TeamIdentifierPrefix)$(CFBundleIdentifier) as the value for iCloud Key-Value Store. I've verified the variables resolve as expected. When I parse the provisioning profile there is no entitlement value for key-value storage. What am I getting wrong?

I have a single multiplatform application that I use NSPersistentCloudKitContainer on. This works great, except I noticed when I open two instances of the same process (not windows) on the same computer, which share the same store, data duplication and "Metadata Inconsistency" errors start appearing. This answer (https://stackoverflow.com/a/67243833) says this is not supported with NSPersistentCloudKitContainer. Is this indeed true? If it isn't allowed, is the only solution to disable multiple instances of the process via a lock file? I was thinking one could somehow coordinate a single "leader" process that syncs to the cloud, with the others using NSPersistentContainer, but this would be complicated when the "leader" process terminates. Currently, it seems iPad split views are new windows, not processes -- but overall I'm still curious :0 Thank you!

What have people's experience with converting locally stored app data to a more browser based accessible format? Firebase seems expensive, Subabase a bit more challenging, and CloudKit too restrictive.

Hi everyone, In the simple app below, I have a QueryView that has LazyVStack containing 100k TextField's that edit the item's content. The items are fetched with a @Query. On launch, the app will generate 100k items. Once created, when I press any of the TextField's , a severe hang happens, and every time I type a single character, it will cause another hang over and over again. I looked at it in Instruments and it shows that the main thread is busy during the duration of the hang (2.31 seconds) updating QueryView. From the cause and effect graph, the update is caused by @Observable QueryController <Item>.(Bool). Why does it take too long to recalculate the view, given that it's in a LazyVStack? (In other words, why is the hang duration directly proportional to the number of items?) How to fix the performance of this app? I thought adding LazyVStack was all I need to handle the large dataset, but maybe I need to add a custom pagination with .fetchLimit on top of that? (I understand that ModelActor would be an alternative to @Query because it will make the database operations happen outside of the main thread which will fix this problem, but with that I will lose the automatic fetching of @Query.) Thank you for the help! import SwiftData import SwiftUI @main struct QueryPerformanceApp: App { var body: some Scene { WindowGroup { ContentView() .modelContainer(for: [Item.self], inMemory: true) } } } @Model final class Item { var name: String init(name: String) { self.name = name } } struct ItemDetail: View { @Bindable var item: Item var body: some View { TextField("Name", text: $item.name) } } struct QueryView: View { @Query private var items: [Item] var body: some View { ScrollView { LazyVStack { ForEach(items) { item in VStack { ItemDetail(item: item) } } } } } } struct ContentView: View { let itemCount = 100_000 @Environment(\.modelContext) private var context @State private var isLoading = true var body: some View { Group { if isLoading { VStack(spacing: 16) { ProgressView() Text("Generating \(itemCount) items...") } } else { QueryView() } } .task { for i in 1...itemCount { context.insert(Item(name: "Item \(i)")) } try? context.save() isLoading = false } } }

Hi everyone, I’m working on an offline-first iOS app using Core Data. I have a question about safe future updates: in my project, I want to be able to add new optional fields to existing Entities or even completely new Entities in future versions — but nothing else (no renaming, deleting, or type changes). Here’s how my current PersistenceController looks: import CoreData struct PersistenceController { static let shared = PersistenceController() let container: NSPersistentContainer init(inMemory: Bool = false) { container = NSPersistentContainer(name: "MyApp") if inMemory { container.persistentStoreDescriptions.first!.url = URL(fileURLWithPath: "/dev/null") } container.loadPersistentStores(completionHandler: { (storeDescription, error) in if let error = error as NSError? { print("Core Data failed to load store: \(error), \(error.userInfo)") } }) container.viewContext.automaticallyMergesChangesFromParent = true } } Do I need to explicitly set these properties to ensure lightweight migration works? shouldMigrateStoreAutomatically = true shouldInferMappingModelAutomatically = true Or, according to the documentation, are they already true by default, so I can safely add optional fields and new Entities in future versions without breaking users’ existing data? Thanks in advance for your guidance!

Hi everyone, We’re currently using CKSyncEngine to sync all our locally persisted data across user devices (iOS and macOS) via iCloud. We’ve noticed something strange and reproducible: On iOS, when the CKSyncEngine is initialized with manual sync behavior, both manual calls to fetchChanges() and sendChanges() happen nearly instantly (usually within seconds). Automatic syncing is also very fast. On macOS, when the CKSyncEngine is initialized with manual sync behavior, fetchChanges() and sendChanges() are also fast and responsive. However, once CKSyncEngine is initialized with automatic syncing enabled on macOS: sendChanges() still appears to transmit changes immediately. But automatic fetching becomes significantly slower — often taking minutes to pick up changes from the cloud, even when new data is already available. Even manual calls to fetchChanges() behave as if they’re throttled or delayed, rather than performing an immediate fetch. Our questions: Is this delay in automatic (and post-automatic manual) fetch behavior on macOS expected, or possibly a bug? Are there specific macOS constraints that impact CKSyncEngine differently than on iOS? Once CKSyncEngine has been initialized in automatic mode, is fetchChanges() no longer treated as a truly manual trigger? Is there a recommended workaround to enable fast sync behavior on macOS — for example, by sticking to manual sync configuration and triggering sync using a CKSubscription-based mechanism when remote changes occur? Any guidance, clarification, or experiences from other developers (or Apple engineers) would be greatly appreciated — especially regarding maintaining parity between iOS and macOS sync performance. Thanks in advance!