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iCloud Database Errors and Limits
We are currently implementing a custom iCloud sync for our macOS and iOS apps using CloudKit. Syncing works fine as long as the number of record sends is relatively small. But when we test with a large number of changes ( 80,000+ CKRecords ) we start running into problems. Our sending strategy is very conservative to avoid rate limits: We send records sequentially in batches of 250 records With about 2 seconds pause between operations Records are small and contain no assets (assets are uploaded separately) At some point we start receiving: “Database commit size exceeds limit” After that, CloudKit begins returning rate-limit errors with retryAfter-Information in the error. We wait for the retry time and try again, but from this moment on, nothing progresses anymore. Every subsequent attempt fails. We could not find anything in the official documentation regarding such a “commit size” limit or what triggers this failure state. So my questions are: Are there undocumented limits on the total number of records that can exist in an iCloud database (private or shared)? Is there a maximum volume of record modifications a container can accept within a certain timeframe, even if operations are split into small batches with pauses? Is it possible that sending large numbers of records in a row can temporarily or permanently “stall” a CloudKit container? Any insights or experiences would be greatly appreciated. Thank you!
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6d
macOS to macOS SwiftData iCloud Sync Problems
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.
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275
Feb ’26
SwiftData+Cloudkit and records with CKAsset import on fresh install never ends.
I’m using SwiftData with CloudKit and running into an issue during initial sync on a fresh device. I’m importing a small set of records, some records has images as CKAsset (with about 5 images ~3MB). Records indexes are the default ones for the Dev env. The problem is that the import process never seems to complete. However, if I delete those records that contains the assets from the iCloud Dashboard, the import finishes successfully. Has anyone experienced something similar? What approach would you recommend to handle this without implementing a custom sync layer on top of CloudKit? I am logging remote changes events (NSPersistentStoreRemoteChange): CloudKit import in progress...|2026-04-25 22:18:10| Then I see: Background Task 49 ("CoreData: CloudKit Import"), was created over 30 seconds ago. In applications running in the background, this creates a risk of termination. Remember to call UIApplication.endBackgroundTask(_:) for your task in a timely manner to avoid this. And then the import never ends. Thanks!
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334
Apr ’26
CloudKit to WebUI
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.
0
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138
Aug ’25
CKSyncEngine on macOS: Automatic Fetch Extremely Slow Compared to iOS
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!
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193
Oct ’25
SwiftData - Cloudkit stopped syncing
I have an app that from day 1 has used Swiftdata and successfully sync'd across devices with Cloudkit. I have added models to the data in the past and deployed the schema and it continued to sync across devices. Sometime I think in June.2025 I added a new model and built out the UI to display and manage it. I pushed a version to Test Flight (twice over a matter of 2 versions and a couple of weeks) and created objects in the new model in Test Flight versions of the app which should push the info to Cloudkit to update the schema. When I go to deploy the schema though there are no changes. I confirmed in the app that Cloudkit is selected and it's point to the correct container. And when I look in Cloudkit the new model isn't listed as an indes. I've pushed deploy schema changes anyway (more than once) and now the app isn't sync-ing across devices at all (even the pre-existing models aren't sync-ing across devices). I even submitted the first updated version to the app store and it was approved and released. I created objects in the new model in production which I know doesn't create the indexes in the development environment. But this new model functions literally everywhere except Cloudkit and I don't know what else to do to trigger an update.
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271
Sep ’25
SwiftData .autosaveEnabled / rollback() trouble
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.
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291
Dec ’25
NSPersistentCloudKitContainer in duplicate processes
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!
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366
Jan ’26
Recommended way to display user-friendly iCloud Drive paths?
I’m building a macOS app that stores file URLs/bookmarks and displays file locations in the UI. For files in iCloud Drive, I want to show a user-friendly path such as: iCloud Drive / My Folder / File.jpg rather than an internal filesystem path. What is the recommended way to display iCloud Drive paths in a way that matches what users see in Finder? Thanks!
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2d
Xcode 26: Sendable checking + NSManagedObjectContext.perform in Swift 6
I have some code which handles doing some computation on a background thread before updating Core Data NSManagedObjects by using the NSManagedObjectContext.perform functions. This code is covered in Sendable warnings in Xcode 26 (beta 6) because my NSManagedObject subclasses (autogenerated) are non-Sendable and NSManagedObjectContext.perform function takes a Sendable closure. But I can't really figure out what I should be doing. I realize this pattern is non-ideal for Swift concurrency, but it's what Core Data demands AFAIK. How do I deal with this? let moc = object.managedObjectContext! try await moc.perform { object.completed = true // Capture of 'object' with non-Sendable type 'MySpecialObject' in a '@Sendable' closure try moc.save() } Thanks in advance for your help!
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187
Aug ’25
CloudKit container may need indexing
My queries are failing in an unusual way. I can query 4 out of 5 Record Types. The 5th fails from the app (CKQueryOperation) and, surprisingly, also from the CloudKit Dashboard. It returns only 100-300 records when it should return over 4000. Tapping "Query Records" returns an additional 100-300 records. Apple Developer Technical Support has suggested that the issue involves the index of the container and wrote that only the CloudKit Team can fix it. So my question is - How do I get the CloudKit Team to fix it????
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2d
Best Practices for Using CKAssets in Public CloudKit Database for Social Features
Hello Apple Team, We are looking at developing an iOS feature on our current development that stores user-generated images as CKAssets in the public CloudKit database, with access control enforced by our app’s own logic (not CloudKit Sharing as that has a limit of 100 shares per device). Each story or post is a public record, and users only see content based on buddy relationships handled within the app. We’d like to confirm that this pattern is consistent with Apple’s best practices for social features. Specifically: Is it acceptable to store user-uploaded CKAssets in the public CloudKit database, as long as access visibility is enforced by the app? Are there any performance or quota limitations (e.g., storage, bandwidth, or user sync limits) that apply to CKAssets in the public database when used at scale? Would CloudKit Sharing be recommended instead, even if we don’t require user-to-user sharing invitations? For App Review, is this model (public CKAssets + app-enforced access control) compliant with Apple’s data and security expectations? Are there any caching or bandwidth optimization guidelines for handling image-heavy public CKAsset data in CloudKit? Thanks again for your time
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Oct ’25
Core Data: Main actor-isolated property can not be mutated from a Sendable closure
I'm running a project with these settings: Default Actor Isolation: MainActor Approachable Concurrency: Yes Strict Concurrency Checking: Complete (this issue does not appear on the other two modes) I receive a warning for this very simple use case. Can I actually fix anything about this or is this a case of Core Data not being entirely ready for this? In reference to this, there was a workaround listed in the release notes of iOS 26 beta 5 (https://forums.swift.org/t/defaultisolation-mainactor-and-core-data-background-tasks/80569/22). Does this still apply as the only fix for this? This is a simplified sample meant to run on a background context. The issue obviously goes away if this function would just run on the MainActor, then I can remove the perform block entirely. class DataHandler { func createItem() async { let context = ... await context.perform { let newGame = Item(context: context) /// Main actor-isolated property 'timestamp' can not be mutated from a Sendable closure newGame.timestamp = Date.now // ... } } } The complete use case would be more like this: nonisolated struct DataHandler { @concurrent func saveItem() async throws { let context = await PersistenceController.shared.container.newBackgroundContext() try await context.perform { let newGame = Item(context: context) newGame.timestamp = Date.now try context.save() } } }
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608
Oct ’25
NSFileVersion.currentVersionOfItem not consistent across devices after simultaneous edit
I’m building an app that edits files in iCloud and uses an NSFilePresenter to monitor changes. When a conflict occurs, the system calls presentedItemDidGain(_:). In that method, I merge the versions by reading the current (canonical) version using NSFileVersion.currentVersionOfItem(at:) and the conflicting ones using NSFileVersion.unresolvedConflictVersionsOfItem(at:). This generally works, but sometimes, if two devices edit the same file at the same time, each device sees its own local version as the current one. For example: Device A writes fileVerA (slightly later in real time) Device B writes fileVerB On Device A all works fine, currentVersionOfItem returns fileVerA, as expected, and unresolvedConflictVersionsOfItem returns [fileVerB]. But on Device B, currentVersionOfItem returns fileVerB!? And unresolvedConflictVersionsOfItem returns the same, local file [fileVerB], without any hint of the other conflicting version, fileVerA. Later, the newer version from the Device A arrives on Device B as a normal, non-conflicting update via presentedItemDidChange(_:). This seems to contradict Apple’s documentation: “The currentVersionOfItemAtURL: method returns an NSFileVersion object representing what’s referred to as the current file; the current file is chosen by iCloud on some basis as the current “conflict winner” and is the same across all devices.” Is this expected behavior, or a bug in how iCloud reports file versions?
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335
Oct ’25
Cannot Accept CloudKit Share After First App Install
I have an iOS app (1Address) which allows users to share their address with family and friends using CloudKit Sharing. Users share their address record (CKRecord) via a share link/url which when tapped allows the receiving user to accept the share and have a persistent view into the sharing user's address record (CKShare). However, most users when they recieve a sharing link do not have the app installed yet, and so when a new receiving user taps the share link, it prompts them to download the app from the app store. After the new user downloads the app from the app store and opens the app, my understanding is that the system (iOS) will/should then vend to my app the previously tapped cloudKitShareMetadata (or share url), however, this metadata is not being vended by the system. This forces the user to re-tap the share link and leads to some users thinking the app doesn't work or not completing the sharing / onboarding flow. Is there a workaround or solve for this that doesn't require the user to tap the share link a second time? In my scene delegate I am implementing: func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {...} And also func scene(_ scene: UIScene, continue userActivity: NSUserActivity) {...} And also: func windowScene(_ windowScene: UIWindowScene, userDidAcceptCloudKitShareWith cloudKitShareMetadata: CKShare.Metadata) {...} And: func scene(_ scene: UIScene, openURLContexts URLContexts: Set<UIOpenURLContext>) {...} Unfortunately, none of these are called or passed metadata on the initial app run after install. Only after the user goes back and taps a link again can they accept the share. This documentation: https://developer.apple.com/documentation/cloudkit/ckshare says that adding the CKSharingSupported key to your app's Info.plist file allows the system to launch your app when a user taps or clicks a share URL, but it does not clarify what should happen if your app is being installed for the first time. This seems to imply that the system is holding onto the share metadata and/or url, but for some reason it is not being vended to the app on first run. Open to any ideas here for how to fix and I also filed feedback: FB20934189.
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Jan ’26
CloudKit: Records not indexing
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.
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1.2k
Apr ’26
Missing demo project
Hi forum! I’m currently following a series of videos about SwiftData. In the WWDC23 Build an app with SwiftData video, it mentions that you can follow up with a demo project. However, I’m encountering an issue (at least in my case) where there’s no link on the entire page to download the project. I can download the video and other resources (even using the Developer’s App), but there’s no link for the project. Does anyone else face this issue? Is it possible that the project has been removed? I’m using my developer (single user) account, by the way. Any guidance would be greatly appreciated!
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628
Mar ’26
SwiftData property marked ephemeral getting persisted in CloudKit
Am I misunderstanding the expected behavior here, or is there a bug in the behavior of @Attribute(.ephemeral) tagged SwiftData model properties? The documentation for .ephemeral says "Track changes to this property but do not persist". I started using .ephemeral because @Transient was inhibiting SwiftUI from reacting to changes to the property through @Observable. I am updating the value of my @Attribute(.ephemeral) property about once a second and I am seeing corresponding console log output showing the property as part of the generated CKRecord object. I then confirmed in the CloudKit dev portal that the .ephemeral property was added to the Record schema and contains real values. The behavior seems as though the .ephemeral property is being completely ignored. This is observed in a new Xcode project using SwiftData with CloudKit, Xcode 16.2, macOS 15.3.1 and during Build & Run testing on physical devices.
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1.2k
Apr ’26
Advanced Data Protection and CloudKit Console.
I enabled Advanced Data Protection for my developer account, and this (understandably) broke access to my private records in CloudKit Console. I disabled Advanced Data Protection but CloudKit Console still cannot connect. In the database popup the "Click here to retry..." option always fails silently. Does anyone know a workaround?
Replies
5
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1
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1.5k
Activity
1w
iCloud Database Errors and Limits
We are currently implementing a custom iCloud sync for our macOS and iOS apps using CloudKit. Syncing works fine as long as the number of record sends is relatively small. But when we test with a large number of changes ( 80,000+ CKRecords ) we start running into problems. Our sending strategy is very conservative to avoid rate limits: We send records sequentially in batches of 250 records With about 2 seconds pause between operations Records are small and contain no assets (assets are uploaded separately) At some point we start receiving: “Database commit size exceeds limit” After that, CloudKit begins returning rate-limit errors with retryAfter-Information in the error. We wait for the retry time and try again, but from this moment on, nothing progresses anymore. Every subsequent attempt fails. We could not find anything in the official documentation regarding such a “commit size” limit or what triggers this failure state. So my questions are: Are there undocumented limits on the total number of records that can exist in an iCloud database (private or shared)? Is there a maximum volume of record modifications a container can accept within a certain timeframe, even if operations are split into small batches with pauses? Is it possible that sending large numbers of records in a row can temporarily or permanently “stall” a CloudKit container? Any insights or experiences would be greatly appreciated. Thank you!
Replies
1
Boosts
1
Views
263
Activity
6d
macOS to macOS SwiftData iCloud Sync Problems
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.
Replies
4
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0
Views
275
Activity
Feb ’26
SwiftData+Cloudkit and records with CKAsset import on fresh install never ends.
I’m using SwiftData with CloudKit and running into an issue during initial sync on a fresh device. I’m importing a small set of records, some records has images as CKAsset (with about 5 images ~3MB). Records indexes are the default ones for the Dev env. The problem is that the import process never seems to complete. However, if I delete those records that contains the assets from the iCloud Dashboard, the import finishes successfully. Has anyone experienced something similar? What approach would you recommend to handle this without implementing a custom sync layer on top of CloudKit? I am logging remote changes events (NSPersistentStoreRemoteChange): CloudKit import in progress...|2026-04-25 22:18:10| Then I see: Background Task 49 ("CoreData: CloudKit Import"), was created over 30 seconds ago. In applications running in the background, this creates a risk of termination. Remember to call UIApplication.endBackgroundTask(_:) for your task in a timely manner to avoid this. And then the import never ends. Thanks!
Replies
1
Boosts
0
Views
334
Activity
Apr ’26
CloudKit to WebUI
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.
Replies
0
Boosts
1
Views
138
Activity
Aug ’25
CKSyncEngine on macOS: Automatic Fetch Extremely Slow Compared to iOS
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!
Replies
1
Boosts
1
Views
193
Activity
Oct ’25
good morning having trouble testing my ckshare code in testflight
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
Replies
3
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0
Views
412
Activity
Dec ’25
SwiftData - Cloudkit stopped syncing
I have an app that from day 1 has used Swiftdata and successfully sync'd across devices with Cloudkit. I have added models to the data in the past and deployed the schema and it continued to sync across devices. Sometime I think in June.2025 I added a new model and built out the UI to display and manage it. I pushed a version to Test Flight (twice over a matter of 2 versions and a couple of weeks) and created objects in the new model in Test Flight versions of the app which should push the info to Cloudkit to update the schema. When I go to deploy the schema though there are no changes. I confirmed in the app that Cloudkit is selected and it's point to the correct container. And when I look in Cloudkit the new model isn't listed as an indes. I've pushed deploy schema changes anyway (more than once) and now the app isn't sync-ing across devices at all (even the pre-existing models aren't sync-ing across devices). I even submitted the first updated version to the app store and it was approved and released. I created objects in the new model in production which I know doesn't create the indexes in the development environment. But this new model functions literally everywhere except Cloudkit and I don't know what else to do to trigger an update.
Replies
3
Boosts
1
Views
271
Activity
Sep ’25
SwiftData .autosaveEnabled / rollback() trouble
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.
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3
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1
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291
Activity
Dec ’25
NSPersistentCloudKitContainer in duplicate processes
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!
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1
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1
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366
Activity
Jan ’26
Recommended way to display user-friendly iCloud Drive paths?
I’m building a macOS app that stores file URLs/bookmarks and displays file locations in the UI. For files in iCloud Drive, I want to show a user-friendly path such as: iCloud Drive / My Folder / File.jpg rather than an internal filesystem path. What is the recommended way to display iCloud Drive paths in a way that matches what users see in Finder? Thanks!
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1
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0
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64
Activity
2d
Xcode 26: Sendable checking + NSManagedObjectContext.perform in Swift 6
I have some code which handles doing some computation on a background thread before updating Core Data NSManagedObjects by using the NSManagedObjectContext.perform functions. This code is covered in Sendable warnings in Xcode 26 (beta 6) because my NSManagedObject subclasses (autogenerated) are non-Sendable and NSManagedObjectContext.perform function takes a Sendable closure. But I can't really figure out what I should be doing. I realize this pattern is non-ideal for Swift concurrency, but it's what Core Data demands AFAIK. How do I deal with this? let moc = object.managedObjectContext! try await moc.perform { object.completed = true // Capture of 'object' with non-Sendable type 'MySpecialObject' in a '@Sendable' closure try moc.save() } Thanks in advance for your help!
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1
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187
Activity
Aug ’25
CloudKit container may need indexing
My queries are failing in an unusual way. I can query 4 out of 5 Record Types. The 5th fails from the app (CKQueryOperation) and, surprisingly, also from the CloudKit Dashboard. It returns only 100-300 records when it should return over 4000. Tapping "Query Records" returns an additional 100-300 records. Apple Developer Technical Support has suggested that the issue involves the index of the container and wrote that only the CloudKit Team can fix it. So my question is - How do I get the CloudKit Team to fix it????
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3
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0
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110
Activity
2d
Best Practices for Using CKAssets in Public CloudKit Database for Social Features
Hello Apple Team, We are looking at developing an iOS feature on our current development that stores user-generated images as CKAssets in the public CloudKit database, with access control enforced by our app’s own logic (not CloudKit Sharing as that has a limit of 100 shares per device). Each story or post is a public record, and users only see content based on buddy relationships handled within the app. We’d like to confirm that this pattern is consistent with Apple’s best practices for social features. Specifically: Is it acceptable to store user-uploaded CKAssets in the public CloudKit database, as long as access visibility is enforced by the app? Are there any performance or quota limitations (e.g., storage, bandwidth, or user sync limits) that apply to CKAssets in the public database when used at scale? Would CloudKit Sharing be recommended instead, even if we don’t require user-to-user sharing invitations? For App Review, is this model (public CKAssets + app-enforced access control) compliant with Apple’s data and security expectations? Are there any caching or bandwidth optimization guidelines for handling image-heavy public CKAsset data in CloudKit? Thanks again for your time
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2
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0
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251
Activity
Oct ’25
Core Data: Main actor-isolated property can not be mutated from a Sendable closure
I'm running a project with these settings: Default Actor Isolation: MainActor Approachable Concurrency: Yes Strict Concurrency Checking: Complete (this issue does not appear on the other two modes) I receive a warning for this very simple use case. Can I actually fix anything about this or is this a case of Core Data not being entirely ready for this? In reference to this, there was a workaround listed in the release notes of iOS 26 beta 5 (https://forums.swift.org/t/defaultisolation-mainactor-and-core-data-background-tasks/80569/22). Does this still apply as the only fix for this? This is a simplified sample meant to run on a background context. The issue obviously goes away if this function would just run on the MainActor, then I can remove the perform block entirely. class DataHandler { func createItem() async { let context = ... await context.perform { let newGame = Item(context: context) /// Main actor-isolated property 'timestamp' can not be mutated from a Sendable closure newGame.timestamp = Date.now // ... } } } The complete use case would be more like this: nonisolated struct DataHandler { @concurrent func saveItem() async throws { let context = await PersistenceController.shared.container.newBackgroundContext() try await context.perform { let newGame = Item(context: context) newGame.timestamp = Date.now try context.save() } } }
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2
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1
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608
Activity
Oct ’25
NSFileVersion.currentVersionOfItem not consistent across devices after simultaneous edit
I’m building an app that edits files in iCloud and uses an NSFilePresenter to monitor changes. When a conflict occurs, the system calls presentedItemDidGain(_:). In that method, I merge the versions by reading the current (canonical) version using NSFileVersion.currentVersionOfItem(at:) and the conflicting ones using NSFileVersion.unresolvedConflictVersionsOfItem(at:). This generally works, but sometimes, if two devices edit the same file at the same time, each device sees its own local version as the current one. For example: Device A writes fileVerA (slightly later in real time) Device B writes fileVerB On Device A all works fine, currentVersionOfItem returns fileVerA, as expected, and unresolvedConflictVersionsOfItem returns [fileVerB]. But on Device B, currentVersionOfItem returns fileVerB!? And unresolvedConflictVersionsOfItem returns the same, local file [fileVerB], without any hint of the other conflicting version, fileVerA. Later, the newer version from the Device A arrives on Device B as a normal, non-conflicting update via presentedItemDidChange(_:). This seems to contradict Apple’s documentation: “The currentVersionOfItemAtURL: method returns an NSFileVersion object representing what’s referred to as the current file; the current file is chosen by iCloud on some basis as the current “conflict winner” and is the same across all devices.” Is this expected behavior, or a bug in how iCloud reports file versions?
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3
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335
Activity
Oct ’25
Cannot Accept CloudKit Share After First App Install
I have an iOS app (1Address) which allows users to share their address with family and friends using CloudKit Sharing. Users share their address record (CKRecord) via a share link/url which when tapped allows the receiving user to accept the share and have a persistent view into the sharing user's address record (CKShare). However, most users when they recieve a sharing link do not have the app installed yet, and so when a new receiving user taps the share link, it prompts them to download the app from the app store. After the new user downloads the app from the app store and opens the app, my understanding is that the system (iOS) will/should then vend to my app the previously tapped cloudKitShareMetadata (or share url), however, this metadata is not being vended by the system. This forces the user to re-tap the share link and leads to some users thinking the app doesn't work or not completing the sharing / onboarding flow. Is there a workaround or solve for this that doesn't require the user to tap the share link a second time? In my scene delegate I am implementing: func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {...} And also func scene(_ scene: UIScene, continue userActivity: NSUserActivity) {...} And also: func windowScene(_ windowScene: UIWindowScene, userDidAcceptCloudKitShareWith cloudKitShareMetadata: CKShare.Metadata) {...} And: func scene(_ scene: UIScene, openURLContexts URLContexts: Set<UIOpenURLContext>) {...} Unfortunately, none of these are called or passed metadata on the initial app run after install. Only after the user goes back and taps a link again can they accept the share. This documentation: https://developer.apple.com/documentation/cloudkit/ckshare says that adding the CKSharingSupported key to your app's Info.plist file allows the system to launch your app when a user taps or clicks a share URL, but it does not clarify what should happen if your app is being installed for the first time. This seems to imply that the system is holding onto the share metadata and/or url, but for some reason it is not being vended to the app on first run. Open to any ideas here for how to fix and I also filed feedback: FB20934189.
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2
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1
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345
Activity
Jan ’26
CloudKit: Records not indexing
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.
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5
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1.2k
Activity
Apr ’26
Missing demo project
Hi forum! I’m currently following a series of videos about SwiftData. In the WWDC23 Build an app with SwiftData video, it mentions that you can follow up with a demo project. However, I’m encountering an issue (at least in my case) where there’s no link on the entire page to download the project. I can download the video and other resources (even using the Developer’s App), but there’s no link for the project. Does anyone else face this issue? Is it possible that the project has been removed? I’m using my developer (single user) account, by the way. Any guidance would be greatly appreciated!
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1
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628
Activity
Mar ’26
SwiftData property marked ephemeral getting persisted in CloudKit
Am I misunderstanding the expected behavior here, or is there a bug in the behavior of @Attribute(.ephemeral) tagged SwiftData model properties? The documentation for .ephemeral says "Track changes to this property but do not persist". I started using .ephemeral because @Transient was inhibiting SwiftUI from reacting to changes to the property through @Observable. I am updating the value of my @Attribute(.ephemeral) property about once a second and I am seeing corresponding console log output showing the property as part of the generated CKRecord object. I then confirmed in the CloudKit dev portal that the .ephemeral property was added to the Record schema and contains real values. The behavior seems as though the .ephemeral property is being completely ignored. This is observed in a new Xcode project using SwiftData with CloudKit, Xcode 16.2, macOS 15.3.1 and during Build & Run testing on physical devices.
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3
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1.2k
Activity
Apr ’26