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CloudKit Documentation

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CloudKit with Unreal Engine
Hi everyone, Im trying to set up CloudKit for my Unreal Engine 5.4 project but seem to be hitting some roadblocks on how to set up the Record Types. From my understanding I need to set up a "file" record type with a "contents" asset field - but even with this it doesn't seem to work :( Any unreal engine devs with some experience on this who could help me out? Thanks!
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118
Sep ’25
Suspicious CloudKit Telemetry Data
Starting 20th March 2025, I see an increase in bandwidth and latency for one of my CloudKit projects. I'm using NSPersistentCloudKitContainer to synchronise my data. I haven't changed any CloudKit scheme during that time but shipped an update. Since then, I reverted some changes from that update, which could have led to changes in the sync behaviour. Is anyone else seeing any issues? I would love to file a DTS and use one of my credits for that, but unfortunately, I can't because I cannot reproduce it with a demo project because I cannot travel back in time and check if it also has an increase in metrics during that time. Maybe an Apple engineer can green-light me filing a DTS request, please.
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134
Apr ’25
SwiftData - disable Persistent History Tracking
Hello, I am building a pretty large database (~40MB) to be used in my SwiftData iOS app as read-only. While inserting and updating the data, I noticed a substantial increase in size (+ ~10MB). A little digging pointed to ACHANGE and ATRANSACTION tables that apparently are dealing with Persistent History Tracking. While I do appreciate the benefits of that, I prefer to save space. Could you please point me in the right direction?
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106
Apr ’25
Will transferring app affect iCloud's Documents folder access?
My app uses iCloud to let users sync their files via their private iCloud Drive, which does not use CloudKit. FileManager.default.url(forUbiquityContainerIdentifier: nil)?.appending(component: "Documents") I plan to transfer my app to another developer account, but I'm afraid it will affect the access of the app to the existing files in that folder. Apple documentation doesn't mention this case. Has anyone done this before and can confirm if the app will continue to work normally after transferring? Thanks
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93
May ’25
CloudKit sync fails across TestFlight iOS + macOS builds — “Field recordName is not marked queryable”
I’m running into a CloudKit sync issue that I can’t reconcile after multiple rebuilds, TestFlight uploads, and entitlement verification, and I’m hoping for guidance on what I’m missing or whether this is expected behavior. Context App: RankSpinnah Platforms: iOS + macOS Distribution: TestFlight Xcode: 26.x Both apps use the same bundle identifier, same container, and same Apple Developer team Automatic signing enabled; Xcode-managed profiles CloudKit capability enabled for both targets Both builds install and run correctly from TestFlight on: iPhone 17 Pro Apple-silicon Mac (M5 MacBook Pro) The Problem CloudKit data does not sync at all between devices. On both iOS and macOS, CloudKit queries return no records, and I consistently see this error: Field 'recordName' is not marked queryable This occurs even when querying for records that should exist and after fresh installs on both devices. What I’ve Verified Same iCloud account signed in on both devices CloudKit container exists and is enabled App Sandbox enabled with network access CloudKit entitlements present in the signed app (verified from the archived .app) TestFlight builds are using the correct container Rebuilt and re-uploaded after version bump (1.2.0 / build 2026.02.03) Both iOS and macOS apps successfully uploaded and installed via TestFlight Despite this, no data syncs, and the queryable error persists. What I’m Unsure About Whether recordName is expected to be non-queryable in production schemas Whether TestFlight + CloudKit requires an explicit production schema deploy beyond what Xcode manages Whether this indicates a schema mismatch between development and production environments Or whether something subtle changed in recent Xcode / CloudKit behavior Ask Can someone clarify: Whether querying by recordName should work in production CloudKit What specifically causes the “Field recordName is not marked queryable” error in TestFlight builds What steps are required to ensure CloudKit schemas are correctly deployed for cross-platform sync At this point I feel like I’m missing one critical step, but I can’t identify what it is. Thanks in advance for any guidance.
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11h
CloudKit Dashboard completely empty (no containers at all) while Xcode 26 still shows my production container iCloud.gainzCloud and builds fine – Tahoe 26.1 / Xcode 26.0 (17A321)
Hi, I’m completely stuck with a very strange CloudKit problem that started recently and has now killed all iCloud sync for a live production app. What is happening Production container: iCloud.gainzCloud (created ~11 months ago, has been working perfectly until now) In Xcode 26.0 (17A321): → Signing & Capabilities → iCloud is enabled → Container correctly shows as iCloud.gainzCloud → App builds and runs on device/simulator with zero provisioning or container errors CloudKit Dashboard (https://icloud.developer.apple.com/dashboard/): completely blank – “No containers found” Result: CloudKit sync is dead for every user (development + production environments) What I know for sure Apple Developer Support confirmed the container iCloud.gainzCloud still exists and is correctly attached to my Team ID on their backend Personal iCloud (Mail, Notes, Photos, etc.) syncs perfectly on the same Mac / same Apple ID under macOS Tahoe 26.1 I have NOT changed the password on either the Apple ID or the Developer Program account New containers I create appear in Xcode but never show up in the Dashboard Environment macOS Tahoe 26.1 (latest) Xcode Version 26.0 (17A321) Has anyone on the new Tahoe/Xcode 26 releases seen the CloudKit Dashboard suddenly go completely empty while Xcode still “sees” the container just fine? Any known trick to force the dashboard to re-index containers or clear whatever cache is broken? Thanks a lot in advance – this is blocking all iCloud functionality for a released app with active users.
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53
Nov ’25
Core Data and Swift 6 concurrency: returning an NSManagedObject
We're in the process of migrating our app to the Swift 6 language mode. I have hit a road block that I cannot wrap my head around, and it concerns Core Data and how we work with NSManagedObject instances. Greatly simplied, our Core Data stack looks like this: class CoreDataStack { private let persistentContainer: NSPersistentContainer var viewContext: NSManagedObjectContext { persistentContainer.viewContext } } For accessing the database, we provide Controller classes such as e.g. class PersonController { private let coreDataStack: CoreDataStack func fetchPerson(byName name: String) async throws -> Person? { try await coreDataStack.viewContext.perform { let fetchRequest = NSFetchRequest<Person>() fetchRequest.predicate = NSPredicate(format: "name == %@", name) return try fetchRequest.execute().first } } } Our view controllers use such controllers to fetch objects and populate their UI with it: class MyViewController: UIViewController { private let chatController: PersonController private let ageLabel: UILabel func populateAgeLabel(name: String) { Task { let person = try? await chatController.fetchPerson(byName: name) ageLabel.text = "\(person?.age ?? 0)" } } } This works very well, and there are no concurrency problems since the managed objects are fetched from the view context and accessed only in the main thread. When turning on Swift 6 language mode, however, the compiler complains about the line calling the controller method: Non-sendable result type 'Person?' cannot be sent from nonisolated context in call to instance method 'fetchPerson(byName:)' Ok, fair enough, NSManagedObject is not Sendable. No biggie, just add @MainActor to the controller method, so it can be called from view controllers which are also main actor. However, now the compiler shows the same error at the controller method calling viewContext.perform: Non-sendable result type 'Person?' cannot be sent from nonisolated context in call to instance method 'perform(schedule:_:)' And now I'm stumped. Does this mean NSManageObject instances cannot even be returned from calls to NSManagedObjectContext.perform? Ever? Even though in this case, @MainActor matches the context's actor isolation (since it's the view context)? Of course, in this simple example the controller method could just return the age directly, and more complex scenarios could return Sendable data structures that are instantiated inside the perform closure. But is that really the only legal solution? That would mean a huge refactoring challenge for our app, since we use NSManageObject instances fetched from the view context everywhere. That's what the view context is for, right? tl;dr: is it possible to return NSManagedObject instances fetched from the view context with Swift 6 strict concurrency enabled, and if so how?
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113
Apr ’25
Is it possible to use an additional local ModelContainer in a document based SwiftData app?
I have a document based SwiftData app in which I would like to implement a persistent cache. For obvious reasons, I would not like to store the contents of the cache in the documents themselves, but in my app's data directory. Is a use case, in which a document based SwiftData app uses not only the ModelContainers from the currently open files, but also a ModelContainer writing a database file in the app's documents directory (for cache, settings, etc.) supported? If yes, how can you inject two different ModelContexts, one tied to the currently open file and one tied to the local database, into a SwiftUI view?
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68
Apr ’25
Saving a file to ubiquitous storage overwrites iCloud version without conflict
Our app saves its data to iCloud by default. In most cases, this is working as intended & the data can be synced across devices with no problems. But recently, in testing, we discovered a situation where it's possible to save data before the NSMetadataQuery finishes & starts downloading the cloud files. When this happens, the query will then finish, and return the NEW file (with no other versions or conflicts). Is there a way to ensure that writing a file (version A) to ubiquitous storage when another version (version B) exists in the cloud is treated as a conflict, rather than just stomping all over the other version? I've tried querying the file metadata for the file URL (NSURLIsUbiquitousItemKey, NSMetadataUbiquitousItemDownloadingStatusKey, NSURLUbiquitousItemDownloadRequestedKey, NSURLUbiquitousItemHasUnresolvedConflictsKey) before saving, but it just returns nil.
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115
Nov ’25
iCloud Mail being rejected by Barracuda Email Protection due to missing PTR record.
My client is using iCloud Mail with his custom domain and he communicated with many govt organizations which seem to all be using Barracuda Email Protection for their spam prevention. I have properly configured his SPF, DKIM & DMARC DNS records however his emails were still being rejected. (Email header below) I contacted Barracuda support with the email header and they replied saying that the emails were rejected becuase Apple Mail has missing PTR records. I have sent dozens of emails for testing and looking at all their headers I can see (ms-asmtp-me-k8s.p00.prod.me.com [17.57.154.37]) which does not have a PTR record. ----FULL EMAIL HEADER WITH 3RD PARTY DOMAINS REMOVED----- <recipient_email_address>: host d329469a.ess.barracudanetworks.com[209.222.82.255] said: 550 permanent failure for one or more recipients (recipient_email_address:blocked) (in reply to end of DATA command) Reporting-MTA: dns; p00-icloudmta-asmtp-us-west-3a-100-percent-10.p00-icloudmta-asmtp-vip.icloud-mail-production.svc.kube.us-west-3a.k8s.cloud.apple.com X-Postfix-Queue-ID: 8979C18013F8 X-Postfix-Sender: rfc822; sender_email_address Arrival-Date: Thu, 20 Mar 2025 12:30:05 +0000 (UTC) Final-Recipient: rfc822; @****** Original-Recipient: rfc822;recipient_email_address Action: failed Status: 5.0.0 Remote-MTA: dns; d329469a.ess.barracudanetworks.com Diagnostic-Code: smtp; 550 permanent failure for one or more recipients (recipient_email_address:blocked) Return-Path: <sender_email_address> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sender_domain; s=sig1; bh=CyUt/U7mIHwXB5OQctPjRH/OxLH7GsLR54JjGuRkj9Y=; h=From:Message-Id:Content-Type:Mime-Version:Subject:Date:To:x-icloud-hme; b=hwEbggsctiCRlMlEgovBTjB/0sPRCb2k+1wzHRZ2dZNrZdOqvFSNWU+Aki9Bl8nfv eEOoXz5qWxO2b2rEBl08lmRQ3hCyroayIn4keBRrgkxL1uu4zMTaDUHyau2vVnzC3h ZmwQtQxiu7QvTS/Sp8jjJ/niOPSzlfhphqMxnQAZi/jmJGcZPadT8K+7+PhRllVnI+ TElJarN1ORQu+CaPGhEs9/F7AIcjJNemnVg1cude7EUuO9va8ou49oFExWTLt7YSMl s+88hxxGu3GugD3eBnitzVo7s7/O9qkIbDUjk3w04/p/VOJ+35Mvi+v/zB9brpYwC1 B4dZP+AhwJDYA== Received: from smtpclient.apple (ms-asmtp-me-k8s.p00.prod.me.com [17.57.154.37]) by p00-icloudmta-asmtp-us-west-3a-100-percent-10.p00-icloudmta-asmtp-vip.icloud-mail-production.svc.kube.us-west-3a.k8s.cloud.apple.com (Postfix) with ESMTPSA id 8979C18013F8; Thu, 20 Mar 2025 12:30:05 +0000 (UTC) From: Marcel Brunel <sender_email_address> Message-Id: <2E8D69EA-FCA6-4F5D-9D42-22A955C073F6@sender_domain> Content-Type: multipart/alternative; boundary="Apple-Mail=_F9AC7D29-8520-4B25-9362-950CB20ADEC5" Mime-Version: 1.0 (Mac OS X Mail 16.0 (3826.400.131.1.6)) Subject: Re: [EXTERNAL] - Re: Brunel - 2024 taxes Date: Thu, 20 Mar 2025 07:29:27 -0500 In-Reply-To: <SA0PR18MB350300DE7274C018F66EEA24F2D82@SA0PR18MB3503_namprd18_prod_outlook_com> To: Troy Womack <recipient_email_address> References: <SA0PR18MB350314D0B88E283C5C8E1BB6F2DE2@SA0PR18MB3503_namprd18_prod_outlook_com> <9B337A3E-D373-48C5-816F-C1884BDA6F42@sender_domain> <SA0PR18MB350341A7172E8632D018A910F2D82@SA0PR18MB3503_namprd18_prod_outlook_com> <SA0PR18MB350300DE7274C018F66EEA24F2D82@SA0PR18MB3503_namprd18_prod_outlook_com> X-Mailer: Apple Mail (2.3826.400.131.1.6) X-Proofpoint-ORIG-GUID: uqebp2OIbPqBr3dYsAxdFVkCNbM5Cxyl X-Proofpoint-GUID: uqebp2OIbPqBr3dYsAxdFVkCNbM5Cxyl X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1093,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-03-20_03,2025-03-19_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 clxscore=1030 suspectscore=0 mlxlogscore=999 mlxscore=0 phishscore=0 malwarescore=0 spamscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2503200077
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194
Mar ’25
ForEach and RandomAccessCollection
I'm trying to build a custom FetchRequest that I can use outside a View. I've built the following ObservableFetchRequest class based on this article: https://augmentedcode.io/2023/04/03/nsfetchedresultscontroller-wrapper-for-swiftui-view-models @Observable @MainActor class ObservableFetchRequest&lt;Result: Storable&gt;: NSObject, @preconcurrency NSFetchedResultsControllerDelegate { private let controller: NSFetchedResultsController&lt;Result.E&gt; private var results: [Result] = [] init(context: NSManagedObjectContext = .default, predicate: NSPredicate? = Result.E.defaultPredicate(), sortDescriptors: [NSSortDescriptor] = Result.E.sortDescripors) { guard let request = Result.E.fetchRequest() as? NSFetchRequest&lt;Result.E&gt; else { fatalError("Failed to create fetch request for \(Result.self)") } request.predicate = predicate request.sortDescriptors = sortDescriptors controller = NSFetchedResultsController(fetchRequest: request, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil) super.init() controller.delegate = self fetch() } private func fetch() { do { try controller.performFetch() refresh() } catch { fatalError("Failed to fetch results for \(Result.self)") } } private func refresh() { results = controller.fetchedObjects?.map { Result($0) } ?? [] } var predicate: NSPredicate? { get { controller.fetchRequest.predicate } set { controller.fetchRequest.predicate = newValue fetch() } } var sortDescriptors: [NSSortDescriptor] { get { controller.fetchRequest.sortDescriptors ?? [] } set { controller.fetchRequest.sortDescriptors = newValue.isEmpty ? nil : newValue fetch() } } internal func controllerDidChangeContent(_ controller: NSFetchedResultsController&lt;any NSFetchRequestResult&gt;) { refresh() } } Till this point, everything works fine. Then, I conformed my class to RandomAccessCollection, so I could use in a ForEach loop without having to access the results property. extension ObservableFetchRequest: @preconcurrency RandomAccessCollection, @preconcurrency MutableCollection { subscript(position: Index) -&gt; Result { get { results[position] } set { results[position] = newValue } } public var endIndex: Index { results.endIndex } public var indices: Indices { results.indices } public var startIndex: Index { results.startIndex } public func distance(from start: Index, to end: Index) -&gt; Int { results.distance(from: start, to: end) } public func index(_ i: Index, offsetBy distance: Int) -&gt; Index { results.index(i, offsetBy: distance) } public func index(_ i: Index, offsetBy distance: Int, limitedBy limit: Index) -&gt; Index? { results.index(i, offsetBy: distance, limitedBy: limit) } public func index(after i: Index) -&gt; Index { results.index(after: i) } public func index(before i: Index) -&gt; Index { results.index(before: i) } public typealias Element = Result public typealias Index = Int } The issue is, when I update the ObservableFetchRequest predicate while searching, it causes a Index out of range error in the Collection subscript because the ForEach loop (or a List loop) access a old version of the array when the item property is optional. List(request, selection: $selection) { item in VStack(alignment: .leading) { Text(item.content) if let information = item.information { // here's the issue, if I leave this out, everything works Text(information) .font(.callout) .foregroundStyle(.secondary) } } .tag(item.id) .contextMenu { if Item.self is Client.Type { Button("Editar") { openWindow(ClientView(client: item as! Client), id: item.id!) } } } } Is it some RandomAccessCollection issue or a SwiftUI bug?
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140
May ’25
Document based SwiftData apps do not autosave
Document based SwiftData apps do not autosave changes to the ModelContext at all. This issue has been around since the first release of this SwiftData feature. In fact, the Apple WWDC sample project (https://developer.apple.com/documentation/swiftui/building-a-document-based-app-using-swiftdata) does not persist any data in its current state, unless one inserts modelContext.save() calls after every data change. I have reported this under the feedback ID FB16503154, as it seemed to me that there is no feedback report about the fundamental issue yet. Other posts related to this problem: https://forums.developer.apple.com/forums/thread/757172 https://forums.developer.apple.com/forums/thread/768906 https://developer.apple.com/forums/thread/764189
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318
Feb ’25
Using Observation class for multiple SwiftData Models
Greetings i have an app that uses three different SwiftData models and i want to know what is the best way to use the them accross the app. I though a centralized behaviour and i want to know if it a correct approach.First let's suppose that the first view of the app will load the three models using the @Enviroment that work with @Observation. Then to other views that add data to the swiftModels again with the @Environment. Another View that will use the swiftData models with graph and datas for average and min and max.Is this a corrent way? or i should use @Query in every view that i want and ModelContext when i add the data. @Observable class CentralizedDataModels { var firstDataModel: [FirstDataModel] = [] var secondDataModel: [SecondDataModel] = [] var thirdDataModel: [ThirdDataModel] = [] let context: ModelContext init(context:ModelContext) { self.context = context } }
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137
Jun ’25
Prevent data loss from delayed schema deployment
Hi all, I recently discovered that I forgot to deploy my CloudKit schema changes from development to production - an oversight that unfortunately went unnoticed for 2.5 months. As a result, any data created during that time was never synced to iCloud and remains only in the local CoreData store. Once I pushed the schema to production, CloudKit resumed syncing new changes as expected. However, this leaves me with a gap: there's now a significant amount of data that would be lost if users delete or reinstall the app. Before I attempt to implement a manual backup or migration strategy, I was wondering: Does NSPersistentCloudKitContainer keep track of local changes that couldn't be synced doe to the missing schema and automatically reattempt syncing them now that the schema is live? If not, what would be the best approach to ensure this "orphaned" data gets saved to CloudKit retroactively. Thanks in advance for any guidance or suggestions.
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151
Jun ’25
SwiftData fails to migrate on new model property
Greetings my fellow engineers, I use SwiftData in my iOS app. The schema is unversioned and consists of a single model. I've been modifying the model for almost two years now and relying on automatic database migrations. I had no problems for all that time, but now trying to add a property to the model or even remove a property from the model results in an error which seems like SwiftData is no longer capable of performing an automatic migration. The log console has things like the following: CoreData: error: NSUnderlyingError : Error Domain=NSCocoaErrorDomain Code=134190 "(null)" UserInfo={reason=Each property must have a unique renaming identifier} CoreData: error: reason : Can't find or automatically infer mapping model for migration CoreData: error: storeType: SQLite CoreData: error: configuration: default CoreData: annotation: options: CoreData: annotation: NSMigratePersistentStoresAutomaticallyOption : 1 CoreData: annotation: NSInferMappingModelAutomaticallyOption : 1 CoreData: annotation: NSPersistentStoreRemoteChangeNotificationOptionKey : 1 CoreData: annotation: NSPersistentHistoryTrackingKey : 1 CoreData: error: <NSPersistentStoreCoordinator: 0x7547b5480>: Attempting recovery from error encountered during addPersistentStore: 0x753f8d800 Error Domain=NSCocoaErrorDomain Code=134140 "Persistent store migration failed, missing mapping model." Have you ever encountered such an issue? What are my options?
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82
Dec ’25
NSMetadataQuery not searching subdirectories in external ubiquity container
Testing Environment: iOS 18.4.1 / macOS 15.4.1 I am working on an iOS project that aims to utilize the user's iCloud Drive documents directory to save a specific directory-based file structure. Essentially, the app would create a root directory where the user chooses in iCloud Drive, then it would populate user generated files in various levels of nested directories. I have been attempting to use NSMetadataQuery with various predicates and search scopes but haven't been able to get it to directly monitor changes to files or directories that are not in the root directory. Instead, it only monitors files or directories in the root directory, and any changes in a subdirectory are considered an update to the direct children of the root directory. Example iCloud Drive Documents (Not app's ubiquity container) User Created Root Directory (Being monitored) File A Directory A File B An insertion or deletion within Directory A would only return a notification with userInfo containing data for NSMetadataQueryUpdateChangedItemsKey relating to Directory A, and not the file or directory itself that was inserted or deleted. (Query results array also only contain the direct children.) I have tried all combinations of these search scopes and predicates with no luck: query.searchScopes = [ rootDirectoryURL, NSMetadataQueryUbiquitousDocumentsScope, NSMetadataQueryAccessibleUbiquitousExternalDocumentsScope, ] NSPredicate(value: true) NSPredicate(format: "%K LIKE '*.md'", NSMetadataItemFSNameKey) NSPredicate(format: "%K BEGINSWITH %@", NSMetadataItemPathKey, url.path(percentEncoded: false)) I do see these warnings in the console upon starting my query: [CRIT] UNREACHABLE: failed to get container URL for com.apple.CloudDocs [ERROR] couldn't fetch remote operation IDs: NSError: Cocoa 257 "The file couldn’t be opened because you don’t have permission to view it." "Error returned from daemon: Error Domain=com.apple.accounts Code=7 "(null)"" But I am not sure what to make of that, since it does act normally for finding updates in the root directory. Hopefully this isn't a limitation of the API, as the only alternative I could think of would be to have multiple queries running for each nested directory that I needed updates for.
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134
May ’25
iCloud Drive changes in iOS 18.4 and later break stated API
The NSMetadataUbiquitousItemDownloadingStatusKey indicates the status of a ubiquitous (iCloud Drive) file. A key value of NSMetadataUbiquitousItemDownloadingStatusDownloaded is defined as indicating there is a local version of this file available. The most current version will get downloaded as soon as possible . However this no longer occurs since iOS 18.4. A ubiquitous file may remain in the NSMetadataUbiquitousItemDownloadingStatusDownloaded state for an indefinite period. There is a workaround: call [NSFileManager startDownloadingUbiquitousItemAtURL: error:] however this shouldn't be necessary, and introduces delays over the previous behaviour. Has anyone else seen this behaviour? Is this a permanent change? FB17662379
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127
May ’25
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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185
Nov ’25
Developing App User Privacy
Hey everyone, I have a question. When creating an app, how should I design a message table that involves personal privacy? The content is stored locally on the user's device, and then encrypted in the server database? How should I design it?
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54
Jan ’26
Consequences of incorrect VersionedSchema.versionIdentifier
About 4 months ago, I shipped the first version of my app with 4 versioned schemas that, unintentionally, had the same versionIdentifier of 1.2.0 in 2 of them: V1: 1.0.0 V2: 1.1.0 V3: 1.2.0 V4: 1.2.0 They are ordered correctly in the MigrationPlan, and they are all lightweight. Migration works, SwiftData doesn't crash on init and I haven't encountered any issues related to this. The app syncs with iCloud. Questions, preferable for anybody with knowledge of SwiftData internals: What will break in SwiftData when there are 2 duplicate numbers? Not that I would expect it to be safe, but does it happen to be safe to ship an update that changes V4's version to 1.3.0, what was originally intended?
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160
Jul ’25