Both the old Mod Organizer 1 Legacy version, and the latest version of MO2 do this. I try to launch the game, the screen goes black as if it's launching the game, and then it instantly closes and boots me back to the desktop. No error messages, no freezing, nothing. It does this more often than not when I try and launch my game, but there's absolutely no consistency to it. Some days, it will open without any problems every single time, whereas other days, it just isn't happening. Restarting my computer sometimes makes it more inclined to launch, but there's no guarantee of anything. I'm positive that Mod Organizer is doing this, because when I try to launch NV through steam, it works fine. I also tried to launch NV through MO from a totally clean file with no mods whatsoever, and it still instantly crashed to desktop. So, it isn't caused by mods, and it isn't NV itself, so it has to be MO. Again, there are no error messages. I try to launch the game, the screen goes black for a half-second, then it just goes back to the desktop.