I'm using SwiftData with CloudKit and have been trying to migrate from SchemaV1 to SchemaV2, but it seems reducing the Entities crashes my app. // Example of migrating from V1 to V2 // Dropping `Person` because it's no longer needed do { // SchemaV1: Person.self, Author.self // SchemaV2: Author.self let schema = Schema(versionedSchema: SchemaV2.self) return try ModelContainer( for: schema, migrationPlan: AppSchemaMigrationPlan.self, configurations: ModelConfiguration( cloudKitDatabase: .automatic) ) } catch { fatalError("Could not create ModelContainer: \(error)") } Is it possible to drop Entities in the Schema Migration Plan? How can I delete the Person model from my Schema and CloudKit?

I'm a first time developer for Swift, (getting on a bit!) but after programming in VB back in the late 90s I wanted to write an app for iPhone. I think I might have gone about it the wrong way, but I've got an app that works great on my iPhone or works great on my iPad. It saves the data persistently on device, but, no matter how much I try, what I read and even resorting to AI (ChatGPT & Gemini) I still can't get it to save the data on iCloud to synchronise between the two and work across the devices. I think it must be something pretty fundamental I'm doing (or more likely not doing) that is causing the issue. I'm setting up my signing and capabilities as per the available instructions but I always get a fatal error. I think it might be something to do with making fields optional, but at this point I'm second guessing myself and feeling a complete failure. Any advice or pointers would be really gratefully appreciated. I like my app and would like eventually to get it on the App Store but at this point in time I feel it should be on the failed projects heap! I've even tried a new Xcode project for iOS and asking it to use SwiftData and CloudKit - the default project should work - right? But it absolutely doesn't for me. Please send help!!

iOS 18.2, Swift, Xcode 16.2 I have a Core Data model with two entities - WarehouseArea (of which there is only one object) and StockReeipt (of which there are a couple of hundred thousand). Each StockReceipt must be linked to a WarehouseArea, and a WarehouseArea can be linked to zero, one or many StockReceipts. My problem is that when I create and add one more StockReceipt, the Core Data save takes over 3 seconds to complete. I don't understand why this is so slow. Saving the initial 200,000 StockReceipts only takes 5-6 seconds. When I enable SQL logging I can see that when the WarehouseArea attribute is being set on a StockReceipt, Core Data fetches all of the other StockReceipts (I don't know why) but that only takes 0.2 seconds and none of those StockReceipts are modified, so there shouldn't be any need to process them when saving the context. I have prepared a test project which can be found at https://github.com/DaleReilly/CoreDataSaveTester . Running the project will produce NSLog output showing the times before and after the slow save. Please help me understand what is going on in the background and tell me if there is any way I can speed this up?

I have an issue in my app, where the crashing frame is an assertionFailure in BackingData.set inside SwiftData framework. My own app doesn't appear until frame 14. I have no idea what causes this, or even how to create a reproducible project as this only happens on some devices. The frame prior to the assertionFailure is this: #1 (null) in BackingData.set(any:value:) () It seems like there is a backing data encoding happening in my Model class, and some value is causing it to fail. The model being accessed is through a relationship, and the frame in the app crashing is along the lines of Text(parent.child.name) Obviously, something is wrong in how I have made child, but the part that stand out to me is the assertionFailure in a release build

Hi, I'm getting a very odd error log in my SwiftData setup for an iOS app. It is implemented to support schema migration. When starting the app, it simply prints the following log twice (seems to be dependent on how many migration steps, I have two steps in my sample code): CoreData: error: Attempting to retrieve an NSManagedObjectModel version checksum while the model is still editable. This may result in an unstable verison checksum. Add model to NSPersistentStoreCoordinator and try again. (Yes there is a mistyped word "verison", this is exactly the log) The code actually fully works. But I have neither CloudKit configured, nor is this app in Production yet. I'm still just developing. Here is the setup and code to reproduce the issue. Development mac version: macOS 15.5 XCode version: 16.4 iOS Simulator version: 18.5 Real iPhone version: 18.5 Project name: SwiftDataDebugApp SwiftDataDebugApp.swift: import SwiftUI import SwiftData @main struct SwiftDataDebugApp: App { var sharedModelContainer: ModelContainer = { let schema = Schema([ Item.self, ]) let modelConfiguration = ModelConfiguration(schema: schema, isStoredInMemoryOnly: false, allowsSave: true) do { return try ModelContainer(for: schema, migrationPlan: ModelMigraitonPlan.self, configurations: [modelConfiguration]) } catch { fatalError("Could not create ModelContainer: \(error)") } }() var body: some Scene { WindowGroup { ContentView() } .modelContainer(sharedModelContainer) } } Item.swift: import Foundation import SwiftData typealias Item = ModelSchemaV2_0_0.Item enum ModelSchemaV1_0_0: VersionedSchema { static var versionIdentifier = Schema.Version(1, 0, 0) static var models: [any PersistentModel.Type] { [Item.self] } @Model final class Item { var timestamp: Date init(timestamp: Date) { self.timestamp = timestamp } } } enum ModelSchemaV2_0_0: VersionedSchema { static var versionIdentifier = Schema.Version(2, 0, 0) static var models: [any PersistentModel.Type] { [Item.self] } @Model final class Item { var timestamp: Date var tags: [Tag] = [] init(timestamp: Date, tags: [Tag]) { self.timestamp = timestamp self.tags = tags } } } enum ModelMigraitonPlan: SchemaMigrationPlan { static var schemas: [any VersionedSchema.Type] { [ModelSchemaV1_0_0.self] } static var stages: [MigrationStage] { [migrationV1_0_0toV2_0_0] } static let migrationV1_0_0toV2_0_0 = MigrationStage.custom( fromVersion: ModelSchemaV1_0_0.self, toVersion: ModelSchemaV2_0_0.self, willMigrate: nil, didMigrate: { context in let items = try context.fetch(FetchDescriptor<ModelSchemaV2_0_0.Item>()) for item in items { item.tags = Array(repeating: "abc", count: Int.random(in: 0...3)).map({ Tag(value: $0) }) } try context.save() } ) } Tag.swift: import Foundation struct Tag: Codable, Hashable, Comparable { var value: String init(value: String) { self.value = value } static func < (lhs: Tag, rhs: Tag) -> Bool { return lhs.value < rhs.value } static func == (lhs: Tag, rhs: Tag) -> Bool { return lhs.value == rhs.value } func hash(into hasher: inout Hasher) { hasher.combine(value) } } ContentView.swift: import SwiftUI import SwiftData struct ContentView: View { @Environment(\.modelContext) private var modelContext @Query private var items: [Item] var body: some View { VStack { List { ForEach(items) { item in VStack(alignment: .leading) { Text(item.timestamp, format: Date.FormatStyle(date: .numeric, time: .standard)) HStack { ForEach(item.tags, id: \.hashValue) { tag in Text("\(tag.value)") } } } } .onDelete(perform: deleteItems) } Button("Add") { addItem() } .padding(.top) } } private func addItem() { withAnimation { let newItem = Item(timestamp: Date(), tags: [Tag(value: "Hi")]) modelContext.insert(newItem) } do { try modelContext.save() } catch { print("Error saving add: \(error.localizedDescription)") } } private func deleteItems(offsets: IndexSet) { withAnimation { for index in offsets { modelContext.delete(items[index]) } } do { try modelContext.save() } catch { print("Error saving delete: \(error.localizedDescription)") } } } #Preview { ContentView() .modelContainer(for: Item.self, inMemory: true) } I hope someone can help, couldn't find anything related to this log at all.

Hey all, This is my first app with Swift, and first app using CloudKit / iCloud - although I have launched other iOS app successfully. When I created the app, I selected "none" for storage my bundle identifier looks like this: io.mysite.appname I have the iCloud capability added, with CloudKit checked, and the container also checked that looks like this: iCloud.io.mysite.appname Push Notificaitons capability is also added, but there is no configuration. I have tried automatically managed signing, as well as a manually created provisioning profile.. Every time I build the app onto my device - when I check it out in settings, icloud is not listed. When I go through iCloud into icloud drive, the app is also not listed. I have cleaned the build many times, deleted and reinstalled the app on my phone many times. I am definitely logged into iCloud etc. Obviously I have spent plenty of times trying to debug with various LLMs, but we all seem to be at a loss for what I'm missing or doing wrong. Would love any tips or pointers I may be missing, thank you!

In the CloudKit logs I see logs that suggest users getting QUOTA_EXCEEDED error for RecordDelete operations. { "time":"21/07/2025, 7:57:46 UTC" "database":"PRIVATE" "zone":"***" "userId":"***" "operationId":"***" "operationGroupName":"2.3.3(185)" "operationType":"RecordDelete" "platform":"iPhone" "clientOS":"iOS;18.5" "overallStatus":"USER_ERROR" "error":"QUOTA_EXCEEDED" "requestId":"***" "executionTimeMs":"177" "interfaceType":"NATIVE" "recordInsertBytes":54352 "recordInsertCount":40 "returnedRecordTypes":"_pcs_data" } I'm confused as to what this means? Why would a RecordDelete operation have recordInsertBytes? I'd expect a RecordDelete operation to never fail on quotaExceeded and how would I handle that in the app?

I have transitioned to CKSyncEngine for syncing data to iCloud, and it is working quite well. I have a question regarding best practices for modifying and saving a CKRecord which already exists in the private or shared database. In my current app, most CKRecords will never be modified after saving to the database, so I do not persist a received record locally after updating my local data model. In the rare event that the local data for that record is modified, I manually fetch the associated server record from the database, modify it, and then use CKSyncEngine to save the modified record. As an alternative method, I can create a new CKRecord locally with the corresponding recordID and the modified data, and then use CKSyncEngine to attempt to save that record to the database. Doing so generates an error in the delegate method handleSentRecordZoneChanges, where I receive the local record I tried to save back inevent.failedRecordSaves with a .serverRecordChanged error, along with the corresponding server CKRecord. I can then update that server record with the local data and re-save using CKSyncEngine. I have not yet seen any issues when doing it this way. The advantage of the latter method is that CKSyncEngine handles the entire database operation, eliminating the manual fetch step. My question is: is this an acceptable practice, or could this result in other unforeseen issues?

Here’s the situation: • You’re downloading a huge list of data from iCloud. • You’re saving it one by one (sequentially) into SwiftData. • You don’t want the SwiftUI view to refresh until all the data is imported. • After all the import is finished, SwiftUI should show the new data. The Problem If you insert into the same ModelContext that SwiftUI’s @Environment(.modelContext) is watching, each insert may cause SwiftUI to start reloading immediately. That will make the UI feel slow, and glitchy, because SwiftUI will keep trying to re-render while you’re still importing. How to achieve this in Swift Data ?

What is the best way to switch between Core Data Persistent Stores? My use case is that I have a multi-user app that stores thousands of data items unique to each user. To me, having Persistent Stores for each user seems like the best design to keep their data separate and private. (If anyone believes that storing the data for all users in one Persistent Store is a better design, I'd appreciate hearing from them.) Customers might switch users 5 to 10 times a day. Switching users must be fast, say a second or two at most.

I’m getting a 0xdead10cc crash in a basic CoreData/CloudKit application. I only have one CoreData save call and its made when the app is in the foreground and it's minor so I don't think its being caused by that. My best guess is that it's related to background syncing of CloudKit. Does anyone know how to fix it? I've been advised that adding the following code around any saves will fix it, but it seems weird that this is the solution. I would expect the inner CoreData/CloudKit engine to handle this. ProcessInfo().performActivity(reason: "Persisting to context") { // Save to context here } Here is the crashing thread Thread 7: 0 libsystem_kernel.dylib 0x00000001edc086f4 guarded_pwrite_np + 8 (:-1) 1 libsqlite3.dylib 0x00000001ca71b6e4 seekAndWrite + 456 (sqlite3.c:44287) 2 libsqlite3.dylib 0x00000001ca6d5df4 unixWrite + 180 (sqlite3.c:44365) 3 libsqlite3.dylib 0x00000001ca723b90 pagerWalFrames + 872 (sqlite3.c:67093) 4 libsqlite3.dylib 0x00000001ca6d5b14 sqlite3PagerCommitPhaseOne + 316 (sqlite3.c:70409) 5 libsqlite3.dylib 0x00000001ca6c6494 sqlite3BtreeCommitPhaseOne + 172 (sqlite3.c:81106) 6 libsqlite3.dylib 0x00000001ca6c605c vdbeCommit + 1136 (sqlite3.c:94124) 7 libsqlite3.dylib 0x00000001ca69f778 sqlite3VdbeHalt + 1340 (sqlite3.c:94534) 8 libsqlite3.dylib 0x00000001ca6c0618 sqlite3VdbeExec + 42648 (sqlite3.c:103922) 9 libsqlite3.dylib 0x00000001ca6b56c0 sqlite3_step + 960 (sqlite3.c:97886) 10 CoreData 0x00000001a459ab38 _execute + 128 (NSSQLiteConnection.m:4614) 11 CoreData 0x00000001a45fe004 -[NSSQLiteConnection commitTransaction] + 728 (NSSQLiteConnection.m:3278) 12 CoreData 0x00000001a469888c _executeGenerateObjectIDRequest + 388 (NSSQLCore_Functions.m:6021) 13 CoreData 0x00000001a46986a4 -[NSSQLGenerateObjectIDRequestContext executeRequestCore:] + 28 (NSSQLObjectIDRequestContext.m:42) 14 CoreData 0x00000001a45fb380 -[NSSQLStoreRequestContext executeRequestUsingConnection:] + 240 (NSSQLStoreRequestContext.m:183) 15 CoreData 0x00000001a45fb0a8 __52-[NSSQLDefaultConnectionManager handleStoreRequest:]_block_invoke + 60 (NSSQLConnectionManager.m:307) 16 CoreData 0x00000001a45fafe0 __37-[NSSQLiteConnection performAndWait:]_block_invoke + 48 (NSSQLiteConnection.m:755) 17 libdispatch.dylib 0x00000001a4357fa8 _dispatch_client_callout + 20 (object.m:576) 18 libdispatch.dylib 0x00000001a43677fc _dispatch_lane_barrier_sync_invoke_and_complete + 56 (queue.c:1104) 19 CoreData 0x00000001a45b5ba4 -[NSSQLiteConnection performAndWait:] + 176 (NSSQLiteConnection.m:752) 20 CoreData 0x00000001a45b5a68 -[NSSQLDefaultConnectionManager handleStoreRequest:] + 248 (NSSQLConnectionManager.m:302) 21 CoreData 0x00000001a45b5938 -[NSSQLCoreDispatchManager routeStoreRequest:] + 228 (NSSQLCoreDispatchManager.m:60) 22 CoreData 0x00000001a45b573c -[NSSQLCore dispatchRequest:withRetries:] + 172 (NSSQLCore.m:4044) 23 CoreData 0x00000001a46737b4 -[NSSQLCore _obtainPermanentIDsForObjects:withNotification:error:] + 1324 (NSSQLCore.m:2830) 24 CoreData 0x00000001a460ba98 -[NSSQLCore _prepareForExecuteRequest:withContext:error:] + 272 (NSSQLCore.m:2946) 25 CoreData 0x00000001a460a0f8 __65-[NSPersistentStoreCoordinator executeRequest:withContext:error:]_block_invoke.547 + 8988 (NSPersistentStoreCoordinator.m:2995) 26 CoreData 0x00000001a45d6660 -[NSPersistentStoreCoordinator _routeHeavyweightBlock:] + 264 (NSPersistentStoreCoordinator.m:668) 27 CoreData 0x00000001a45ded28 -[NSPersistentStoreCoordinator executeRequest:withContext:error:] + 1200 (NSPersistentStoreCoordinator.m:2810) 28 CoreData 0x00000001a4655988 -[NSManagedObjectContext save:] + 984 (NSManagedObjectContext.m:1593) 29 CoreData 0x00000001a46f47dc __52+[NSCKEvent beginEventForRequest:withMonitor:error:]_block_invoke_2 + 352 (NSCKEvent.m:76) 30 CoreData 0x00000001a45c28f0 developerSubmittedBlockToNSManagedObjectContextPerform + 476 (NSManagedObjectContext.m:3984) 31 libdispatch.dylib 0x00000001a4357fa8 _dispatch_client_callout + 20 (object.m:576) 32 libdispatch.dylib 0x00000001a43677fc _dispatch_lane_barrier_sync_invoke_and_complete + 56 (queue.c:1104) 33 CoreData 0x00000001a4615c34 -[NSManagedObjectContext performBlockAndWait:] + 308 (NSManagedObjectContext.m:4108) 34 CoreData 0x00000001a46f45ac __52+[NSCKEvent beginEventForRequest:withMonitor:error:]_block_invoke + 192 (NSCKEvent.m:66) 35 CoreData 0x00000001a4825e68 -[PFCloudKitStoreMonitor performBlock:] + 92 (PFCloudKitStoreMonitor.m:148) 36 CoreData 0x00000001a46f4394 +[NSCKEvent beginEventForRequest:withMonitor:error:] + 256 (NSCKEvent.m:61) 37 CoreData 0x00000001a47cc6ec __57-[NSCloudKitMirroringDelegate _performExportWithRequest:]_block_invoke + 260 (NSCloudKitMirroringDelegate.m:1433) 38 CoreData 0x00000001a47c9970 __92-[NSCloudKitMirroringDelegate _openTransactionWithLabel:assertionLabel:andExecuteWorkBlock:]_block_invoke + 72 (NSCloudKitMirroringDelegate.m:957) 39 libdispatch.dylib 0x00000001a4356248 _dispatch_call_block_and_release + 32 (init.c:1549) 40 libdispatch.dylib 0x00000001a4357fa8 _dispatch_client_callout + 20 (object.m:576) 41 libdispatch.dylib 0x00000001a435f5cc _dispatch_lane_serial_drain + 768 (queue.c:3934) 42 libdispatch.dylib 0x00000001a4360158 _dispatch_lane_invoke + 432 (queue.c:4025) 43 libdispatch.dylib 0x00000001a436b38c _dispatch_root_queue_drain_deferred_wlh + 288 (queue.c:7193) 44 libdispatch.dylib 0x00000001a436abd8 _dispatch_workloop_worker_thread + 540 (queue.c:6787) 45 libsystem_pthread.dylib 0x0000000227213680 _pthread_wqthread + 288 (pthread.c:2696) 46 libsystem_pthread.dylib 0x0000000227211474 start_wqthread + 8 (:-1)

I have a ModelActor that creates a hierarchy of models and returns a PersistentIdentifier for the root. I'd like to do that in a transaction, but I don't know of a good method of getting that identifier if the models are created in a transaction. For instance, an overly simple example: func createItem(timestamp: Date) throws -> PersistentIdentifier { try modelContext.transaction { let item = Item(timestamp: timestamp) modelContext.insert(item) } // how to return item.persistentModelID? } I can't return the item.persistentModelID from the transaction closure and even if I could, it will be a temporary ID until after the transaction is executed. I can't create the Item outside the transaction and just have the transaction do an insert because swift will raise a data race error if you then try to return item.persistentModelID. Is there any way to do this besides a modelContext.fetch* with separate unique identifiers?

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

I have some models in my app: [SDPlanBrief.self, SDAirport.self, SDChart.self, SDIndividualRunwayAirport.self, SDLocationBrief.self] SDLocationBrief has a @Relationship with SDChart When I went live with my app I didn't have a versioned schema, but quickly had to change that as I needed to add items to my SDPlanBrief Model. The first versioned schema I made included only the model that I had made a change to. static var models: [any PersistentModel.Type] { [SDPlanBrief.self] } I had made zero changes to my model container and the whole time, and it was working fine. The migration worked well and this is what I was using: .modelContainer(for: [SDAirport.self, SDIndividualRunwayAirport.self, SDLocationBrief.self, SDChart.self, SDPlanBrief.self]) I then saw that to do this all properly, I should actually include ALL of my @Models in the versioned schema: enum AllSwiftDataSchemaV3: VersionedSchema { static var models: [any PersistentModel.Type] { [SDPlanBrief.self, SDAirport.self, SDChart.self, SDIndividualRunwayAirport.self, SDLocationBrief.self] } static var versionIdentifier: Schema.Version = .init(2, 0, 0) } extension AllSwiftDataSchemaV3 { @Model class SDPlanBrief { var destination: String etc... init(destination: String, etc...) { self.destination = destination etc... } } @Model class SDAirport { var catABMinima: String etc... init(catABMinima: String etc...) { self.catABMinima = catABMinima etc... } } @Model class SDChart: Identifiable { var key: String etc... var brief: SDLocationBrief? // @Relationship with SDChart init(key: String etc...) { self.key = key etc... } } @Model class SDIndividualRunwayAirport { var icaoCode: String etc... init(icaoCode: String etc...) { self.icaoCode = icaoCode etc... } } @Model class SDLocationBrief: Identifiable { var briefString: String etc... @Relationship(deleteRule: .cascade, inverse: \SDChart.brief) var chartsArray = [SDChart]() init( briefString: String, etc... chartsArray: [SDChart] = [] ) { self.briefString = briefString etc... self.chartsArray = chartsArray } } } This is ALL my models in here btw. I saw also that modelContainer needed updating to work better for versioned schemas. I changed my modelContainer to look like this: actor ModelContainerActor { @MainActor static func container() -> ModelContainer { let schema = Schema( versionedSchema: AllSwiftDataSchemaV3.self ) let configuration = ModelConfiguration() let container = try! ModelContainer( for: schema, migrationPlan: PlanBriefMigrationPlan.self, configurations: configuration ) return container } } and I am passing in like so: .modelContainer(ModelContainerActor.container()) Each time I run the app now, I suddenly get this message a few times in a row: CoreData: error: Attempting to retrieve an NSManagedObjectModel version checksum while the model is still editable. This may result in an unstable verison checksum. Add model to NSPersistentStoreCoordinator and try again. I typealias all of these models too for the most recent V3 version eg: typealias SDPlanBrief = AllSwiftDataSchemaV3.SDPlanBrief Can someone see if I am doing something wrong here? It seems my TestFlight users are experiencing a crash every now and then when certain views load (I assume when accessing @Query objects). Seems its more so when a view loads quickly, like when removing a subscription view where the data may not have had time to load??? Can someone please have a look and help me out.

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

I need to know the current date to query CloudKit data with it, like: let predicate = NSPredicate(format: "publishedAt <= %@", currentDateAndTime) I don't need high precision, even +/- a few minutes is fine, but I can't rely on device's time since the user can manually change it. Researching this myself I see that the most reliable method is to get the date from the server. There are NTP servers, but accessing them requires additional libraries which adds complexity. TrueTime (last updated 6 years ago) and Kronos (updated like once a year) seem outdated, given how much Swift has changed in the past years. I can make an HTTP request to a website like Google or Apple and read the current time from its headers. But I don't know if this method is reliable. I know I can create a dummy record in CloudKit, update it, and read its modificationDate. But it feels hacky. Maybe there is another way to fetch the current date directly from CloudKit? It feels like it should be easy and there is a straightforward solution, but I just can't find it.

Does the CloudKit participant limit of 100 include the owner?

Hello, I'm using CoreData + CloudKit and I am facing the following error 134100 "The managed object model version used to open the persistent store is incompatible with the one that was used to create the persistent store." All my schema updates are composed of adding optional attributes to existing entities, adding non-optional attributes (with default value) to existing entities or adding new entities Basically, only things that lightweight migrations can handle. Every time I update the schema, I add a new model version of xcdatamodel - who only has a single configuration (the "Default" one). And I also deploy the updated CloudKit schema from the dashboard. It worked up to v3 of my xcdatamodel, but started to crash for a few users at v4 when I added 16 new attributes (in total) to 4 existing entities. Then again at v5 when I added 2 new optional attributes to 1 existing entity. I'm using a singleton and here is the code: private func generateCloudKitContainer() -> NSPersistentCloudKitContainer { let container = NSPersistentCloudKitContainer(name: "MyAppModel") let fileLocation = URL(...) let description = NSPersistentStoreDescription(url: fileLocation) description.shouldMigrateStoreAutomatically = true description.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey) description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey) let options = NSPersistentCloudKitContainerOptions(containerIdentifier: "iCloud.com.company.MyApp") options.databaseScope = .private description.cloudKitContainerOptions = options container.persistentStoreDescriptions = [description] container.viewContext.automaticallyMergesChangesFromParent = true container.loadPersistentStores { description, error in container.viewContext.mergePolicy = NSMergePolicy(merge: .mergeByPropertyObjectTrumpMergePolicyType) if let error { // Error happens here! } } return container } I can't reproduce it yet. I don't really understand what could lead to this error.

As of 2025-05-03, when a macOS user enables iCloud Drive synchronization for Desktop &amp; Documents in US region, does iCloud filter xattrs upon upload or later when downloading back to another macOS host? Or is it the case that iCloud has no filtering of third-party xattrs? Where can I find the technical document outlining exactly what iCloud does with xattrs set on macOS host files and folders synchronized with iCloud Drive?

I have an app that uses NSPersistentCloudKitContainer stored in a shared location via App Groups so my widget can fetch data to display. It works. But if you reset your iPhone and restore it from a backup, an error occurs: The file "Name.sqlite" couldn't be opened. I suspect this happens because the widget is created before the app's data is restored. Restarting the iPhone is the only way to fix it though, opening the app and reloading timelines does not. Anything I can do to fix that to not require turning it off and on again?