swift

Fatal nil unwrap at runtime

Fatal error: Unexpectedly found nil while unwrapping an Optional value

Fixes

1.Replace force unwrap (!) with optional chaining (?.) or if-let binding
2.Check IBOutlet connections — disconnected outlets are nil at runtime
3.Initialize the property before accessing it

optionalfataliboutlet

Related Errors

SwiftUI preview crash

SwiftUI.*Previews.*crashed.*The preview process was terminated

•Clean build folder: Cmd+Shift+K, then rebuild
•Check for force-unwrapped optionals or fatalError in preview code

Swift Combine publisher cancelled unexpectedly

Swift.*Combine.*Cancelled.*sink received completion.*failure

•Store the AnyCancellable in a Set to prevent premature deallocation
•Use .store(in: &cancellables) to retain the subscription

Core Data model incompatible with persistent store

CoreData.*NSInternalInconsistencyException.*model.*incompatible.*store

•Add a migration mapping model for schema changes
•Use lightweight migration: addPersistentStore with NSMigratePersistentStoresAutomaticallyOption