I have two apps that use App Groups, CloudKit and Core Data for sharing data between multiple devices and users (one is a sample for the issue, the other one the full fledged one). In the sample app I have the following model: Collection (name) -> many Items (names and count) and corresponding views to increment the count. I also have the widget share the proper App Group and CloudKit container. It has a button that triggers an increment app intent. A create a shared collection "Shares" and add two items in it - "A" & "B". Sharing from the applications and updates of the count takes about 2 seconds. I.e. I open the item view and I tap an increment button, the second phone screen updates almost immediately. Upon each update I also call WidgetCenter.shared.reloadAllTimelines(). What I see is that widgets have are not in sync with the data of the app. I have an explicit button to trigger the reload of the timelines, I can follow along with the debugger and the Core Data data is different, i.e. different count. I also show a date property, so I know that the widget is redrawn. I think that as soon as I added the target for the widget and added it to the app group I started seeing: BUG IN CLOUDKIT: Error submitting background task request: Error Domain=BGSystemTaskSchedulerErrorDomain Code=3 "(null)". The sync between the widget and the app on the same device is inconsistent. I also see a lot of when interactions happen fast. submitTaskRequest failed for com.apple.coredata.cloudkit.activity.import. submitTaskRequest failed for com.apple.coredata.cloudkit.activity.export. I least I hope is that after the app has synchronised, the widget will catch-up and show the same data - i.e. at least the same device will show data consistently. This does not happen though. Even on the device on which I'm doing the changes, and tapping multiple times the manual reload of widgets button, the Core Data is stale, and the time of reload of the widget is fine. The relevant threads this I've found are (none of them can shed any light): https://developer.apple.com/forums/thread/653112?answerId=697974022 https://developer.apple.com/forums/thread/650192?answerId=614112022#614112022 https://developer.apple.com/forums/thread/651648?answerId=827386022 I have tested with iOS 26.5.2 and iOS 27 Beta. The widget is it out sync

Description: When a user's iCloud storage is full, the Notes app continues to save recent edits locally to a pending-sync cache. However, if the user toggles iCloud Notes sync to "Off" in System Settings, macOS executes a total database purge script. The system completely ignores error flags indicating that the local edits never successfully reached the cloud server. This creates a critical edge case resulting in permanent user data loss. Requested Change: Implement an explicit safeguard check prior to executing the local cache purge. If local_edits > cloud_edits, the system must present a warning modal stating: "Your most recent edits have not yet uploaded to iCloud due to full storage. Disabling sync will permanently delete these un-saved notes from this device."

I'm adding CloudKit sharing to an app that already uses NSPersistentCloudKitContainer successfully. Private-database sync works flawlessly across my devices. But every attempt to create a share hangs: container.share(_:to:) never returns and never invokes its completion handler. No error is thrown, nothing prints, the operation simply stalls indefinitely. Environment: Xcode 26, iOS 26.5, iPhone 16 Paid Individual developer account Single NSPersistentCloudKitContainer, two stores (private + shared) What works: Private database sync across multiple devices (iPhone + iPad) is reliable eventChangedNotification reports setup/import/export events succeeding continuously CloudKit schema was initialized via initializeCloudKitSchema() and record types appear in the CloudKit Console The problem: Calling share on a root object hangs. I've reproduced the identical hang with all three API variants: async/await: try await container.share([object], to: nil) — never returns Completion handler: container.share([object], to: nil) { ... } — closure never fires UICloudSharingController preparation-closure initializer — the closure never fires, controller presents an empty sheet A log line immediately before the share call prints; a log line inside the completion/closure never does. My two-store setup (per WWDC21 session 10015): swiftlet sharedURL = privateDesc.url! .deletingLastPathComponent() .appendingPathComponent("YerBoat-Shared.sqlite") let sharedDesc = NSPersistentStoreDescription(url: sharedURL) let sharedOptions = NSPersistentCloudKitContainerOptions(containerIdentifier: "iCloud.com.example.app") sharedOptions.databaseScope = .shared sharedDesc.cloudKitContainerOptions = sharedOptions sharedDesc.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey) sharedDesc.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey) container.persistentStoreDescriptions = [privateDesc, sharedDesc] Possibly relevant: the objects I'm trying to share (and their related records via cascade relationships) were all created before I added the sharing/shared-store code. Could existing records in the default zone fail to migrate into a shareable zone, causing the hang? Questions: What causes share() to hang silently with no error and no completion? Does sharing require records to be created after the shared store exists, or should existing private-database records be shareable? Is there a required step between initializeCloudKitSchema() and the first share() call that I'm missing? I've reviewed WWDC21-10015 and TN3164. Any guidance appreciated.

I have a SwiftData app that runs on iOS, iPadOS, and MacCatalyst and which uses CloudKit for inter-device sync. Unfortunately, I also have two AppleIDs (which I 'll refer to as OLDID and NEWID). Although all three devices (phone, pad and desktop) are currently set up with NEWID as the active AppleID, during development and testing, my desktop Mac used OLDID. Apparently, the system remembers the AppleID to use with each CloudKit app (based on the AppleID active at time of first use), because the desktop app and the mobile apps apparently sync to different AppleID accounts. I can delete the local database on the desktop and delete the local app on the mobile devices and in each case, reloading/rerunning the app causes the respective databases to be restored from the cloud. The two mobile devices sync with each other, but not with the desktop; the desktop doesn't sync with either device. And the two databases have decidedly different contents. My goal is to consolidate everything so that there is one database, shared and synced between desktop, pad, phone and cloud. I presume that there is a setting somewhere (but clearly NOT in the app's sandboxed container) that specifies what iCloud account to use for that (and each) app. Note: I have other apps which sync between all my devices, so the setting must be on a per-app basis. I also presume that if I changed it's value on my desktop (so that all three devices used the same AppleID for cloud services for my app), that the content of the local database on my desktop would be synced automatically to the NEWID cloud account and then (also automatically) synchronized with my mobile devices. I.e., I speculate that I can solve all my problems by changing that setting on my desktop Mac. So I have two questions: Is all this correct? How do I make this setting change. (I.e., where is it and how do I change it) Does anyone have any experience and can help with this issue? Thanks

A sandboxed Mac app with correct CloudKit entitlements fails to connect to com.apple.cloudd (the CloudKit daemon) when distributed via TestFlight (Mac Team Store Provisioning Profile). The identical binary works correctly when launched from Xcode (Mac Team Provisioning Profile also present). All entitlements are correctly embedded and the App ID is properly configured in Apple Developer Portal. Environment macOS 26.5.1 (25F80) Xcode 26.5 (17F42) SwiftData with NSPersistentCloudKitContainer / ModelConfiguration(cloudKitDatabase: .private(...)) Steps to Reproduce Create a sandboxed Mac app using SwiftData with CloudKit sync Enable iCloud + CloudKit in Signing & Capabilities Archive and distribute to TestFlight (Mac Team Store Provisioning Profile) Install via TestFlight on macOS 26 and launch Check Console for kernel sandbox messages Expected Result CloudKit connects to com.apple.cloudd and syncs data, matching behavior of the iOS version using the same container. Actual Result Console shows repeated kernel sandbox denials followed by CloudKit setup failure: kernel Sandbox: CheatSheet Mac(82347) deny(1) mach-lookup com.apple.cloudd kernel Sandbox: CheatSheet Mac(82347) deny(1) mach-lookup com.apple.duetactivityscheduler CheatSheet Mac CoreData+CloudKit: Failed to set up CloudKit integration for store Error Domain=CKErrorDomain Code=6 "Error connecting to CloudKit daemon." Key Diagnostic Finding When launched from Xcode, taskgated-helper validates both the Mac Team Store Provisioning Profile AND the Mac Team Provisioning Profile, and CloudKit succeeds: cloudd: TCC approved access for container containerID=iCloud.com.michaelendres.CheatSheet:Production When launched from TestFlight, only the Mac Team Store Provisioning Profile is present, and the sandbox denies com.apple.cloudd despite identical entitlements in the binary: codesign -d --entitlements shows: com.apple.developer.icloud-services: [CloudKit] com.apple.developer.icloud-container-identifiers: [iCloud.com.michaelendres.CheatSheet] com.apple.developer.icloud-container-environment: Production com.apple.security.app-sandbox: true Conclusion The Mac Team Store Provisioning Profile on macOS 26 does not appear to grant the sandbox exception for mach-lookup com.apple.cloudd, while the Mac Team Provisioning Profile (development) does. This prevents any Mac App Store / TestFlight app using CloudKit from syncing on macOS 26.

I could not find iCloud invading capabilities, it Shows nothing found, is there a problem in account or what

Overview Using NotificationCenter's messages NSPersistentCloudKitContainer.EventChangedMessage (AsyncMessage) causes crash When the this project is run on iOS 27 simulator, app crashes Environment macOS: 26.5.1 (25F80) Xcode: Version 27.0 beta (27A5194q) Simulator: iPhone 17 Pro Simulator OS: iOS 27 Code causing the crash: let messages = NotificationCenter.default.messages( of: NSPersistentCloudKitContainer.self, for: .eventChanged ) Looks like the symbol is not even present Feedback: FB23220378 Logs dyld[31078]: Symbol not found: _$sSo29NSPersistentCloudKitContainerC8CoreDataE19EventChangedMessageVSo20NSNotificationCenterC10FoundationE05AsyncI0ACMc Referenced from: <488D9AA6-ED4C-3189-9A08-044D576D498D> /Users/username/Library/Developer/CoreSimulator/Devices/331ADE41-8F3A-4EBE-9E3B-B335B29224D3/data/Containers/Bundle/Application/573DF3FC-E202-4D47-A85F-E5D4D1421EAC/NotificationMessageDemo.app/NotificationMessageDemo.debug.dylib Expected in: <483D9879-24DB-3695-AFE5-B14E2D673F36> /private/var/run/com.apple.security.cryptexd/mnt/com.apple.iPhoneOS.SimulatorRuntime-v24.1.5355.16.mnzElK/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 27.0.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/CoreData.framework/CoreData Symbol not found: _$sSo29NSPersistentCloudKitContainerC8CoreDataE19EventChangedMessageVSo20NSNotificationCenterC10FoundationE05AsyncI0ACMc Referenced from: <488D9AA6-ED4C-3189-9A08-044D576D498D> /Users/username/Library/Developer/CoreSimulator/Devices/331ADE41-8F3A-4EBE-9E3B-B335B29224D3/data/Containers/Bundle/Application/573DF3FC-E202-4D47-A85F-E5D4D1421EAC/NotificationMessageDemo.app/NotificationMessageDemo.debug.dylib Expected in: <483D9879-24DB-3695-AFE5-B14E2D673F36> /private/var/run/com.apple.security.cryptexd/mnt/com.apple.iPhoneOS.SimulatorRuntime-v24.1.5355.16.mnzElK/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 27.0.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/CoreData.framework/CoreData dyld config: DYLD_SHARED_CACHE_DIR=/Library/Developer/CoreSimulator/Caches/dyld/25F80/com.apple.CoreSimulator.SimRuntime.iOS-27-0.24A5355p/ DYLD_ROOT_PATH=/private/var/run/com.apple.security.cryptexd/mnt/com.apple.iPhoneOS.SimulatorRuntime-v24.1.5355.16.mnzElK/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 27.0.simruntime/Contents/Resources/RuntimeRoot DYLD_LIBRARY_PATH=/Users/username/Library/Developer/Xcode/DerivedData/NotificationMessageDemo-gungjtytarzeijdspglltylscocj/Build/Products/Debug-iphonesimulator DYLD_INSERT_LIBRARIES=/private/var/run/com.apple.security.cryptexd/mnt/com.apple.iPhoneOS.SimulatorRuntime-v24.1.5355.16.mnzElK/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 27.0.simruntime/Contents/Resources/RuntimeRoot/usr/lib/libLogRedirect.dylib:/private/var/run/com.apple.security.cryptexd/mnt/com.apple.iPhoneOS.SimulatorRuntime-v24.1.5355.16.mnzElK/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 27.0.simruntime/Contents/Resources/RuntimeRoot/usr/lib/libMainThreadChecker.dylib:/usr/lib/libRPAC.dylib:/private/var/run/com.apple.security.cryptexd/mnt/com.apple.iPhoneOS.SimulatorRuntime-v24.1.5355.16.mnzElK/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 27.0.simruntime/Contents/Resources/RuntimeRoot/usr/lib/libViewDebuggerSupport.dylib DYLD_FRAMEWORK_PATH=/Users/username/Library/Developer/Xcode/DerivedData/NotificationMessageDemo-gungjtytarzeijdspglltylscocj/Build/Products/Debug-iphonesimulator DYLD_FALLBACK_FRAMEWORK_PATH=/private/var/run/com.apple.security.cryptexd/mnt/com.apple.iPhoneOS.SimulatorRuntime-v24.1.5355.16.mnzElK/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 27.0.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks DYLD_FALLBACK_LIBRARY_PATH=/private/var/run/com.apple.security.cryptexd/mnt/com.apple.iPhoneOS.SimulatorRuntime-v24.1.5355.16.mnzElK/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 27.0.simruntime/Contents/Resources/RuntimeRoot/usr/lib Debug session ended with code 9: killed

There’s hundreds of forms of people wanting and waiting for swifitdata support for CloudKit public or shared databases. Is this ever going to come or should I just give up and use my own database dont really want to learn core data for such a small part of my app

I have a SwiftData + CloudKit app that is deployed to the Mac App Store. As a diagram my situation looks like: On my Mac, I have installed the App Store version of the App. When developing it I run the app via Xcode, so I can have a debug build running. The initial stable schema was deployed to CloudKit production before the App release. Now, when I change the SwiftData schema again and run the Debug app on my Mac What happens is that: The SwiftData local store is on the latest schema The CloudKit schema for development is automatically updated That’s all good, but if I run the App Store app version of my app. By default, it uses the same SwiftData store for both builds of the app, which are being synced to different CloudKit schemas for development and production at the same time. As a result, I get an unreliable state where I have seen data duplication as a result, or CloudKit syncing just breaks. Also, since I’m developing the app, the changes to the schema in development may not make it to production, so I don’t want to promote those changes to production. So my question: What’s the recommended way to evolve the schema for an app already on the App Store? I haven’t seen any example or session from Apple that tackles this -what I consider common- use case. I tried to have different CloudKit containers for a "Dev" and "Prod" builds, but that wasn’t the solution.

iCloud KeySyc is a privacy-focused feature that securely syncs a user’s personalized keyboard learning across all Apple devices through iCloud. Today, when users upgrade to a new iPhone or begin using a new iPad or Mac, the keyboard often loses much of the personalization it has developed over time. Users must re-teach autocorrect, rebuild custom vocabulary, and wait for the keyboard to relearn their typing habits. iCloud KeySync would allow users to move seamlessly between devices while keeping the keyboard experience familiar from day one. Problem Statement Apple’s keyboard becomes more useful over time as it learns: Frequently used words and phrases Personal slang and abbreviations Emoji preferences Autocorrect adjustments Writing patterns and typing habits When users switch devices, much of this personalization is lost or takes time to rebuild. This creates friction during device upgrades and reduces the feeling of continuity within the Apple ecosystem. Proposed Solution iCloud KeySync securely synchronizes keyboard personalization data across Apple devices. The feature would: Learn and store personalized keyboard behavior on-device. Encrypt and sync personalization data through iCloud. Restore keyboard preferences automatically when signing into a new device. Keep keyboard learning consistent across iPhone, iPad, and Mac. Key Features Personalized Vocabulary Sync Synchronizes user-added words, nicknames, slang, and frequently used phrases. Emoji Preference Sync Maintains commonly used emoji patterns across devices. Autocorrect Learning Sync Preserves learned corrections and accepted custom spellings. Typing Behavior Continuity Allows devices to share keyboard learning so users receive familiar suggestions regardless of which Apple device they use. User Controls Enable or disable iCloud KeySync. Reset keyboard learning at any time. View privacy information and storage usage. Privacy and Security Privacy should remain the foundation of the feature. All keyboard learning occurs on-device. Personalization data is end-to-end encrypted. Raw message content is never uploaded. Users retain full control over synchronization settings. Security protections match the standards used by iCloud Keychain. User Benefits New devices feel familiar immediately. Less time correcting autocorrect mistakes. Faster onboarding after device upgrades. Consistent typing experience across the Apple ecosystem. Improved customer satisfaction and retention. Example User Scenario A user upgrades from an older iPhone to a new iPhone. After signing into iCloud and restoring their device, the keyboard immediately recognizes their commonly used phrases, preferred emoji, custom words, and learned typing patterns. The new device feels personalized from the first message typed, without requiring weeks of retraining Business Value Improves the upgrade experience. Strengthens ecosystem continuity. Reinforces Apple’s privacy-first approach to AI and machine learning. Creates a subtle but meaningful quality-of-life improvement for millions of users. Switch phones. Keep your vibe.

I have been having this weird issue. Whenever I tap on "Act as iCloud Account" in cloudkit console, my login never works. I have been having this issue for more than 6 months now. ANy one have any insights on this?

Fails with "to-many key not allowed here" // parent.children?.contains(where: { // $0.name == "Abbiejean" // }) != nil parent.children.flatMap { children in children.contains(where: { $0.name == "Abbijean" }) } == true How are we supposed to query on relationships? This is a huge problem. This is a major limitation blocking migration of CoreData to SwiftData. We can do this with NSPredicate: let moodAnalysis = NSPredicate(format: "ANY moodAnalysis.labels.title == %@", label.description) let stateOfMinds = NSPredicate(format: "SUBQUERY(stateOfMinds, $x, SUBQUERY($x.labels, $y, $y.title == %@).@count > 0).@count > 0", label.description) The accepted answer on stack overflow is: you can't Document says that optionals are allowed in predicates The SwiftData team has made a big show of saying that we can use idiomatic swift for our predicates. But we cannot even filter on relationships when the container is backed by CloudKit... That should be a HUGE warning in the documentation. "For those of you who are considering a costly refactor from CoreData to SwiftData, and are currently using CloudKit, all relationships are mandatory optional arrays, and you can't write predicates on them"

I've noticed that new record saves added using add(pendingRecordZoneChanges:) while handling events such as sentRecordZoneChanges or fetchedRecordZoneChanges aren't processed by CKSyncEngine until the app restarts, i.e. the app process has to be terminated and started again for CKSyncEngine to actually attempt to send the pending record saves. This started happening ever since I updated iOS and macOS to 26.5. Is this by design or a bug I should report?

I was experiencing a weird sign in error when using apple sign in with my app and wanted to put it here for anyone else who might experience it in the future, and so apple can make this requirement more clear. I was using CloudKit and apple sign in. If you are not using both this probably does not apply to you. Every time I would go to sign in in the iOS simulator I would enter my password, hit "sign in", and everything just froze. The very odd reason for this is if you are using iCloudKit and apple sign in you need to go to specifically the "identifiers" in the "Certificates, Identifiers & Profiles" menu (https://developer.apple.com/account/resources/identifiers/list). And from there you specifically need an App ID Configuration with apple sign in enabled. From there you have to have the same exact bundle identifier in Xcode under project settings(not an upper tab just click your project in the left panel). And that should allow you to both pass validation and have your sign in work. Hope this helps!

I often struggle to see my own log data with the heavy stream of CloudKit updates. Is there an easy way to filter that our or turn it on/off?

Moved to WWDC26 iCloud & CloudKit Q&A: https://developer.apple.com/forums/thread/830698

Are there good ways to guide an app to pause iCloud syncing if the app is busy with an intensive activity? Also, is there a way to suggest that it check iCloud for updates?

Hi there!, I have been developing an app where you can create a collection and I want to add a new feature where you can share an iCloud link from that collection and collaborate with your family or friends who you share the link to complete that collection. Like Apple does with the notes app or some other apps. The problem I have encountered is programming in swift does not allow you to do that and I need to do it I Core Data... Do you think with all the new stuff announced during the WWDC26 It could be done in Swift or I have to change coding?? Thanks community for any help

See FB22358865. I have a formerly working app. From within the app, Queries to 4 'Record Types' work fine. Queries to one Record Type return only some records. When I 'Query Records' from the CloudKit dashboard I get 100-300 records downloaded for this Record Type. If I repeat 'Query Records' I get an additional 100-300 records. There are more than 4000 records. Apple Developer Technical Support has stated 'the index in your CloudKit container gets in a bad state." How can I fix this?

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!