Hello, we have a file provider based macOS app. Around June we started receiving reports that our users have problems when opening files. Sometimes they get "Invalid argument" alerts after double-clicking on a dataless file. We receive similar errors when trying to materialize the files programmatically from our app (not FP extension)(*): "The operation could not be completed. Invalid argument" code: 22 domain: "NSPOSIXErrorDomain" underlyingError: "cannotMaterialize" code: 33 domain: "libfssync.VFSFileError" We also see those errors with matching timestamps in the output from fileproviderctl dump: > (...) update-item: 🔶 last:(...) (-1min27s) (...) error:'NSError: POSIX 22 "The operation couldn’t be completed. Invalid argument" Underlying={NSError: libfssync.VFSFileError 33 "cannotMaterialize" }}' domain:none category:<nil> (...) At the same time our file provider extension receives fetchPartialContents call or no call at all. If it receives the call it finishes with success and returns correct range: requestedRange: "{0, 15295}" returnedRange: "{0, 524288}" alignment: "16384" Sadly we don't know how to reproduce those issues. We will be grateful for any hints that could be useful in debugging. Some more context: if materializing a file fails with this error, subsequent materialization attempts fail similarly in local testing when downloading a file with the code below, or double-click, we only get regular fetchContents call file returned by fetchPartialContents should have correct size the app is built with XCode 16.1, customers reporting this issue have OS/FP versions: 24F74/2882.120.74 and 24G90/2882.140.30 (*) More or less the code that we use to materialize files func materializeURL(_ url: URL) throws { if try url.isDataless() { var error: NSError? = nil let coordinator = NSFileCoordinator(filePresenter: nil) coordinator.coordinate(readingItemAt: url, error: &error) { _ in } if let error { throw error } } } private extension URL { func isDataless() throws -> Bool { let downloadStatus = try self .resourceValues(forKeys: [.ubiquitousItemDownloadingStatusKey]) .ubiquitousItemDownloadingStatus return downloadStatus == .notDownloaded || downloadStatus == .none } }