So I have two class models, Item and Category, as follows: @Model class Category { let name: String ... } @Model class Item { var name: String var category: Category? ...  } I have a view called ItemDetailsView that displays all the properties of a given item. It also has a toggle that shows an ItemEditorView where user's can edit the item properties, including the category which shows up in a picker. I set up the preview for ItemDetailsView as follows: #Preview { let preview = Preview(Item.self, Category.self) preview.addExamples(Category.sampleCategories) preview.addExamples(Item.sampleItems) return ItemDetailsView(item: Item.sampleItems[0]) .modelContainer(preview.container) } The Preview class sets up my model container and inserts the sample items and categories that I have instantiated as static constant variables. struct Preview { let container: ModelContainer init(_ models: any PersistentModel.Type...) { let schema = Schema(models) let config = ModelConfiguration(isStoredInMemoryOnly: true) do { container = try ModelContainer(for: schema, configurations: config) } catch { fatalError("Could not create preview container") } } func addExamples(_ examples: [any PersistentModel]) { Task { @MainActor in examples.forEach { example in container.mainContext.insert(example) } } } } I'm not sure why my preview is crashing. I had a hunch that it was because we needed all the categories to be available for the picker in ItemEditorView but I already inserted the relevant categories into the model context. Preview is working as expected in a different view called ItemDetailsView which lists all the items added. Navigation links and sheets work perfectly. Not sure why this is giving me trouble.