I can take it out of S mode but cannot go back if I do.
Why on earth would you ever want to go back to S-mode? In my opinion, S-Mode should be called C-mode, where C stands for "Crippled".
Bottom line is, if you want to install TurboTax or any other third party app not purchased from the Windows Store, then you flat out can not so long as you remain in S-Mode.
