I have some user data in my Winstore C# app. I just learnt that local store and app data are being erased after new version of the app is installed (or user reinstalled the app).
How to permanently store the data? Can it be done transparently for the user?
What about enterprise class of apps – how do you guys access more robust data like databases?
You can use something like Skydrive or Dropbox to store the files.
EDIT*
There is no database access support in WinRT. While you can use something like SQLite to store data locally – it would be used mostly for caching and it would be expected that you persist the data somewhere in the cloud, so you should still upload the data you want stored somewhere outside of your machine.
If you want to store files on your machine that don’t get deleted with your app – you can save them somewhere in the documents/pictures/music/videos libraries, depending on where they fit best.