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.
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Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
let myEmail = "eskimo" + "1" + "@apple.com"