The Feedback report is FB21728837. The project is here: https://github.com/benwiggy/ReView

FB number is FB21732645 I'll add information about the action. Thanks.

Thanks. The first problem seems to be finding something that is in the FirstResponder chain that can validate the menu item if there's an image. AppDelegate doesn't seem to work.

Is this still a mystery?

Thanks for the link -- I would never have found that post without being led to it. Many forums have 'sticky' posts or things that new members must read; or a category for Help.

This is the only code I have to open the PDF: override func read(from data: Data, ofType typeName: String) throws { self.thePDFDocument = PDFDocument.init(data: data) if self.thePDFDocument == nil { throw NSError(domain: NSOSStatusErrorDomain, code: unimpErr, userInfo: nil) } } I set the PDFDocument to nil when I close it.

I'm just using openDocument, without overriding it. Yes, the files are on the internal boot volume (APFS). The error was flagged in the UI. TM reported that the backup hadn't completed, and in System Settings it reported the name of the file. It has done this to various files: the only connection is they are all PDFs that are or have been open in my app. Closing the app and running TM fixes the error. As usual, I can't find any relevant logs in Console.

I've been using TM since Leopard, and I have tens of documents regularly open in a variety of applications, and I've never seen this error until I started using my own app. The app's role is an Editor, as it can modify and save files. Nonetheless, TextEdit, Pages, BBEdit, and countless other apps that I use don't have this problem.

Might the document's size be an issue? They tend to be over 100 Mb. It's certainly not ALL the documents that I open: only a few. It's worth saying that I've deliberately switched off the auto-save functionality (autosavesInPlace = false). Can I ask what you mean by "checking the documentEdited property"..? If I close a document with unsaved changes, it flags an alert saying that there are unsaved changes; do you want to save them. If there aren't, then the document closes gracefully. I'll see if I can trigger it again and investigate a bit. Thanks

Oh - one other possible factor: the files are Locked in the Finder, to prevent edits. They've been on a disk for over a year, unchanged, as far as I know.

If there are unsaved changes, then the app should ask to save; and that's not happening. It doesn't seem like I'm doing anything particularly wrong, or omitting something that I ought to be doing; and it only affects a small number of files, and only occasionally. I'll keep an eye on in and see if I can investigate next time it happens. Thanks