There is this common issue when players cant save the game.

Heres the easy solution:

There will open a window that says login to Xbox Live Account wich doesnt work at all.
Click on "Create new Account"
Then click on "confirm" to confirm the User Agreements.
On the next page you scroll down and click on "create local save"

From now on you can save the game, the only bad thing about it is that you cant get achievements on your Account by creating a local save on your computer.

I hope i helped you guys with this easy solution.