I was getting this crash intermittently as others have described, and I believe it was triggered by using a background context on the main thread. I have a class that wraps all CoreData interactions, and it uses NSPersistentContainer to accomplish this. I was using NSPersistentContainer.viewContext for everything which was causing intermittent issues when I accessed it from a background thread. I then added a member called backgroundContext that is initialized using NSPersistentContainer.newBackgroundContext(), and using that for everything is when I ran into the issue that we're all here for. So I added a computed value that uses the appropriate context based on the current thread: private var context: NSManagedObjectContext { Thread.isMainThread ? container.viewContext : backgroundContext } and I use that whenever I need an NSManagedObjectContext. I have not been able to reproduce any CoreData crashes since I made this change. I hope this is helpful to somebody. I'll put the relevant part of my class below for reference. final class CoreDataManager {   // MARK: Singleton   static let shared = CoreDataManager()   private init() { backgroundContext = container.newBackgroundContext() }       // MARK: Constants   private let container: PersistentContainer = {     let container = PersistentContainer(name: "LocalModel")     container.loadPersistentStores { description, error in       if let error = error {         CriticalError.handle(with: "Unable to load persistent stores: \(error)")       }     }     return container   }()       private let backgroundContext: NSManagedObjectContext       // MARK: Computed Values   private var context: NSManagedObjectContext { Thread.isMainThread ? container.viewContext : backgroundContext } }