1st time buying minecraft & can't play it

"Error details: Attempting to move successful download to C:/Users\Sanchez\AppData\Roaming\.minecraft\assets\objects\ac/ac52bce00c6a*****
The process cannot access the file because it is being used by another process"

I have uninstalled & reinstalled minecraft, as well as re-booted but keep getting error. what's the point of buying a game you can't play?