I am trying to get Core Data running with the new Multiplatform SwiftUI on Xcode 12. Since there is no checkbox for Core Data, I looked at some examples on how to build your own Core Data Stack and pass it in. So fare so good. However as soon as I try to make a FetchRequest struct ContentView: View {     @FetchRequest(fetchRequest: Entity.fetchRequest()) var entitys: FetchedResults<Entity>     var body: some View {         Text("Hello, world!")             .padding()     } } My app Crashes with: Fatal error: UnsafeRawBufferPointer with negative count Here my code: import SwiftUI @main struct CoreDataTemplateApp: App {     let context = PersistentCloudKitContainer.persistentContainer.viewContext     var body: some Scene {         WindowGroup {             ContentView()                 .environment(\.managedObjectContext, context)         }     } } I got the PersistentContainer of the form: import CoreData public class PersistentCloudKitContainer {     public static var context: NSManagedObjectContext {         return persistentContainer.viewContext     }     private init() {}     public static var persistentContainer: NSPersistentContainer = {         let container = NSPersistentContainer(name: "Model")         container.loadPersistentStores(completionHandler: { (storeDescription, error) in             if let error = error as NSError? {                 fatalError("Unresolved error \(error), \(error.userInfo)")             }         })         container.viewContext.automaticallyMergesChangesFromParent = true         container.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy         return container     }()     public static func saveContext () {         let context = persistentContainer.viewContext         if context.hasChanges {             do {                 try context.save()             } catch {                 let nserror = error as NSError                 fatalError("Unresolved error \(nserror), \(nserror.userInfo)")             }         }     } } Am I missing something essential here? My Core Data Model is a single entity with a name property.