So this tutorial usually works, but for those like me who did everything in this tutorial and still had issues. I suggest going to your rfactor 2/launcher folder and deleting the Microsoft Access Procedure Shortcut files associated with the track/car/mod that isn't installing. For example, I couldn't install the v 1.03 of Imola 2018. I unsusbcribed, left steam, came back and still had issues. I deleted my locations folder. Still had issues. The only thing that fixed it was deleting the Microsoft Access Procedure Shortcut file that had "Imola 2018" in it. Once i did that it fixed the issue. It must have been stuck on some sort of instruction or command because of that.