I'm testing the new SwiftData to see if I can use it on one of my apps. Specifically I'm trying to learn how to use the schema migrations. I made a new project using Xcode 15 beta 4. I selected to use SwiftData and iCloud. I ran the generated project and I added a couple of items to the screen. Then, I wanted to make a schema migration, so I changed the Item model from: @Model final class Item { var timestamp: Date init(timestamp: Date) { self.timestamp = timestamp } } to also include a string title: @Model final class Item { var timestamp: Date var title: String init(timestamp: Date, title: String) { self.timestamp = timestamp self.title = title } } I also made some changes to the SwiftUI code to include an empty string when adding a new item, so it could compile: let newItem = Item(timestamp: Date(), title: "") And then I added a new file containing the migration, according to what I saw on the video sessions: // // SwiftDataMigrations.swift // Test 1 // // Created by Diego on 12/07/23. // import Foundation import SwiftData enum ItemSchemaV1: VersionedSchema { static var versionIdentifier: String? static var models: [any PersistentModel.Type] { [Item.self] } @Model final class Item { var timestamp: Date init(timestamp: Date) { self.timestamp = timestamp } } } enum ItemSchemaV2: VersionedSchema { static var versionIdentifier: String? static var models: [any PersistentModel.Type] { [Item.self] } @Model final class Item { var timestamp: Date var title: String init(timestamp: Date, title: String) { self.timestamp = timestamp self.title = title } } } enum ItemsMigrationPlan: SchemaMigrationPlan { static var schemas: [any VersionedSchema.Type] { [ItemSchemaV1.self, ItemSchemaV2.self] } static var stages: [MigrationStage] { [migrateV1toV2] } static let migrateV1toV2 = MigrationStage.lightweight(fromVersion: ItemSchemaV1.self, toVersion: ItemSchemaV2.self) } After that, I specified the migrationPlan in the app: // // Test_1App.swift // Test 1 // // Created by Diego on 12/07/23. // import SwiftUI import SwiftData @main struct Test_1App: App { var container = try! ModelContainer( for: Item.self, migrationPlan: ItemsMigrationPlan.self ) var body: some Scene { WindowGroup { ContentView() } .modelContainer(container) } } And then I tried to run the app but it crashed on launch with this error: SwiftData/ModelContext.swift:179: Fatal error: Container does not have any data stores Does anyone have any idea about what I might be missing? The only thing that didn't matched the videos was that when creating a ModelContainer, the code on the video showed var container = ModelContainer... but the compiler showed the error Call can throw, but errors cannot be thrown out of a property initializer, so I added the try!. Also, on the VersionedSchema, I had to add static var versionIdentifier: String?. Other than that I have no idea. Thanks in advance.