Have also had this problem since I upgraded from windows 7 to 10. After booting up Windows 10 for the first time, I managed to download an app or two, but ever since I have not been able to download anything from appstore, appearantly because of the error behind this error-code. It also seems to show up in Windows Update when i click "search for updates", yet the OS manages to stay up to date. Would love to be able to download apps freely, as this is my first encounter with windows appstore.