When integrating SwiftData for an already existing app that uses CoreData as data management, I encounter errors. When building the ModelContainer for the first time, the following error appears: Error: Persistent History (184) has to be truncated due to the following entities being removed (all Entities except for the 2 where I defined a SwiftData Model) class SwiftDataManager: ObservableObject { static let shared = SwiftDataManager() private let persistenceManager = PersistenceManager.shared private init(){} lazy var modelContainer: ModelContainer = { do { let storeUrl = persistenceManager.storeURL() let schema = Schema([ HistoryIncident.self, HistoryEvent.self ]) let modelConfig = ModelConfiguration(url: storeUrl) return try ModelContainer(for: schema, configurations: [modelConfig]) } catch { fatalError("Could not create ModelContainer: \(error)") } }() } @Model public class HistoryIncident { var missionNr: String? @Relationship(deleteRule: .cascade) var events: [HistoryEvent]? public init(){} } @Model class HistoryEvent { var decs: String? var timestamp: Date? init(){} } As soon as I call the following function. func addMockEventsToCurrentHistorie() { var descriptor = FetchDescriptor<HistoryIncident>() let key = self.hKey ?? "" descriptor.predicate = #Predicate { mE in key == mE.key } let historyIncident = try? SwiftDataManager.shared.modelContext.fetch(descriptor).first guard var events = historyIncident?.events else {return} events.append(contentsOf: createEvents()) } I get the error: CoreData: error: (1) I/O error for database at /var/mobile/Containers/Data/Application/55E9D59D-48C4-4D86-8D9F-8F9CA019042D/Library/ Private Documents/appDatabase.sqlite. SQLite error code:1, 'no such column: t0.Z1EVENTS' /var/mobile/Containers/Data/Application/55E9D59D-48C4-4D86-8D9F-8F9CA019042D/Library/ Private Documents/appDatabase.sqlite. SQLite error code:1, 'no such column: t0.Z1EVENTS' with userInfo of { NSFilePath = "/var/mobile/Containers/Data/Application/55E9D59D-48C4-4D86-8D9F-8F9CA019042D/Library/ Private Documents/appDatabase.sqlite"; NSSQLiteErrorDomain = 1; }