NSProgress - way to publish progress to make the file url unselectable in Finder?

So I'm in the middle of an asynchronous file operation. I publish an NSProgress and it displays wonderfully in Finder.

But it is a folder and while the operation is in progress the user should not be allowed to enter it, modify it, etc, while the work is being done. I want to do this to protect the user from doing something silly.

But Finder does not prevent the selection with the published progress. And while it would be kind of dumb to do - the user can just go about adding/removing contents to the folder while it has progress.

If I remember correctly publishing an NSProgress did use to prevent the file from being selectable in Finder until either the progress finished or my app is quit (or maybe not)? But now the user is free to select, edit, modify during progress which could cause problems if the user does something unexpectedly silly.

Is there a way to mark the file 'unselectable' with the published progress?

Thanks in advance.