Wait so your copy of the game is all messed up now?
No no. I didn't have a copy of the game to begin with.
My brother, who lives away from me, has a physical disc copy of TMCC, and he has installed and played it on his Xbox One.
I signed into his account on my Xbox One however, and it came up with TMCC on the dashboard, since it was recently played.
I pressed on it and it started a download of the game. Which surprised me.
I thought it might be the FULL download of the game and that I'd then be able to play TMCC, despite not having the disc nor buying it from the Marketplace.
But all it did was download the additional game files for TMCC.
When you purchase TMCC on a disc and stick it in the Xbox One, you still have to download additional files for the game.
I've downloaded these files, but they don't allow me to play the game.
That would only happen if I purchased TMCC on the marketplace so it was registered on my account, or if I had a copy of the disc.