There’s two ways to use storage in Windows Phone 8 apps:

Isolated Storage

Windows.Storage

So which one should you use? My recommendation: Windows.Storage.And why? Because Isolated Storage isn’t thread safe.

When the app is small and there’s no 3rd party libraries, you can create a wrapper over the Isolated Storage which uses locking to make sure that only one thread can access the Isolated Storage. But as soon as you add a third party library, you’ll lose control: If the library uses Isolated Storage, it will bypass the locking mechanism you have created inside your storage wrapper.

So, in order to save yourself from random exceptions and strange data losses, prefer Windows.Storage over Isolated Storage.