Can you say me what changed between iOS 9 and iOS 10 ? Security ?
I use the MobileDeviceSupport to see the "Documents" directory (sandbox) (and subfolders) of my app.
To be clear, this is not a supported technique, and breakage like this is exactly the reason we encourage developers, even those with apps that don’t go through App Review, to stick to supported techniques.
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
let myEmail = "eskimo" + "1" + "@apple.com"