It would be helpful if you could elaborate a bit on willMigrate and didMigrate. What exactly has to happen? lets assume we got wllMigrate { context in let oldDatamodel = try context.fetch(oldDataModelDescriptor) for oldData in OldDataModel { --> what happens here? } try? context.save() } didMigrate { context in let newDatamodel = try context.fetch(newDataModelDescriptor) for newData in NewDataModel { --> what happens here? } try? context.save() }

thanks, that helped! to translate this into reality, what you mean is: BEFORE #Preview { SomeView() } AFTER #Preview { NavigationView { SomeView() } }

thank you mate!

I'm using SwiftData and this command solved my problem. I am super thankful. Thank you! Also thanks to everybody else for all that helpful ideas like changing the preview device, or emptying ContentView and repopulating it.