The original install was on C:. After a half-dozen attempts to repair that one (including uninstall/reinstall, flushing the Steam cache, etc., etc.) I tried a brand-new install on D:, which lead to the same dead-end as before: a message about "disc write failure" towards the end of the (incomplete) install. My C: and D: are separate SSDs. It's extremely unlikely that both SSDs developed bad sectors (or whatever) at the same moment. Therefore, something bad must be stuck somewhere in some sub-basement of Win10 (yes, I tried W11; hated it). I suppose I could offload everything (we're talking terrabytes here) onto an external drive, reformat C: and D: and start all over again, but I just can't. I've sunk 5 years of my life into this game (which has given me some priceless moments, like winning a league race at my favorite track in my favorite car). I have nothing left to give. So I'm retreating to my private island in the British Virgins (no phone, no TV, no Internet) to lollygag on the beach, sipping margaritas and thinking of you guys. Fins up!