Ok i rescan my games and NMM can find every game no matter what drive except Fallout 4 the GOG version, Have tried to direct it to the correct game but it says it can't find the Fallout 4 Exe yet it is in the directory and no i will not go to that toxic NMM site.

Isn't there a way to get NMM to see the EXE ?

It sees the skyrim on both the steam and the GOG versions i have and it finds the steam version of Fallout 4. And No i will not use Vortex. Worst Mod manager i have ever tried to use.

NMM is simple and easy to use.

All my games are on a M.2 2 terabyte secondary drive. Including my GOG installation.