I honestly can't recall anyone ever having this particular issue before. (And I've been part of the game's fan community since the beginning.)

Since you said you checked the Lithtech.exe compatibility settings: that means it isn't missing from the TRON 2.0 folder, for some reason.

And the game still works fine on the most recent Fall Creators update for Windows 10, so the version of Windows you're running should be irrelevant.

So, apart from that . . . one of the few possibilities I can think of right now, is perhaps an anti-virus/anti-malware/firewall, or some other process running in the background, is blocking Lithtech.exe from executing. (Which is absurd, of course. Since this version of the game doesn't even have any DRM, that a security program might get a false positive result from. But I'd check, anyway.)

As a last resort, you can always install the Unofficial Patch for the game. Which might help, since it replaces the game's executables with more up to date versions. There's a link to a page where you can download it, in this topic.