It means you're selecting the wrong F4 folder.
no, i got the same issue. i tried both the direct map where fallout4.esm is (data inside of fallout 4) and the fallout 4 map which is the normal one.
it can't detect it. didn't had this issues on W10, but i do on the same pc using W7 (i downgraded) after re-installing the game. the game is complete and functions fine.
i am re-installing NNM hoping that's the issue.