I can install The Samaritan Paradox and play it, but every day (real life days, not in-game days) when I come back to the game, the executable samaritan.exe file is not in the game folder anymore. Everything else is there; the save files are intact, the only file that disappears is samaritan.exe. If I reinstall the game I can continue playing. Luckily it's a quick game to install, but this is becoming tedious (I have already done it three times, one for each day I have accessed the game).

I am playing in Windows 10, running through an admin account, offline installers. Any ideas before I contact Support?

That's exactly what was happening! I added an exception to my antivirus.

Thank you very much.