In a SwiftUI DocumentGroup, the "Create Document" button remains permanently disabled when attempting to open a document that is in a conflict state (e.g., due to simultaneous edits across devices). As a result, the user cannot create new documents, and the app becomes stuck. On macOS, the expected conflict resolution dialog appears, and the app continues to function normally. On iOS, however, the "Create Document" button stays disabled indefinitely. This behavior occurs consistently in a default SwiftUI document-based app. Steps to Reproduce: Create a new SwiftUI document-based project in Xcode; Setup iCloud Storage in Signing & Capabilities; Create an empty document and place it in a conflict state (e.g., save it simultaneously from two devices); Attempt to open the conflicted document on an iPhone or iPad; Expected Result: The user should be able to resolve the conflict and continue working; The "Create Document" button should remain functional; Actual Result: The "Create Document" button is disabled permanently; The app cannot create new documents until restarted; Environment; iOS 18, iOS 26 (latest tested); Xcode Version 16.4 (16F6) Reproduced on iPhone and iPad; Works as expected on macOS; This appears to be a blocking issue in SwiftUI’s DocumentGroup on iOS. FB20203775

Steps to reproduce: Create a default document-based app for iOS using SwiftUI or UIKit with UIDocumentViewController. In the document loading method, simulate an error by throwing an exception, for example: throw CocoaError(.coderValueNotFound) Open the app on device/simulator running iOS 18 and attempt to open or create a new document. Expected behavior: An appropriate error message should be displayed to the user. Actual behavior: No error message is shown to the user The "Create Document" button becomes permanently disabled The app appears to hang or become unresponsive Environment: iOS 18, 26 beta 9 Both UIKit and SwiftUI implementations affected Has anyone encountered this issue or found a workaround? This seems like a regression in iOS 18's document handling. FB20189617, FB20189669