iCloud storage with Core Data, introduced with iOS 5 in 2011, was deeply flawed. Those flaws continued with iOS 6 a year later but with the introduction of iOS 7 in June, things were looking up. The team promised no new features and instead a focus on fixing bugs.
Indeed, my work with the feature in my iOS 7 app has generally been great… but when it fails, it falls hard.
With so many copies of my app VegasMate deployed, some users have run into a problem where their iCloud stored data just vanishes when an app update is applied. The current theory is that Core Data has, for some reason, decided to create a new Fallback Store which is of course empty. To the user, this simply looks like their data is gone.
This really stinks.
I’ve been working with Apple and fleshing out a comprehensive bug report so that if this is indeed an iOS bug as it appears, it can be fixed in a future release. In the meantime, I’ve implemented a backup mechanism in my app to help protect users, though that really shouldn’t be necessary.