I installed MO just a few days ago. v1.2.18. It does contain a BSA, though. By count in the Archives tab, I'm only using 16 BSAs beyond those in the base game & DLC.
For whatever reason, MO won't load up the game while I have the New Bison Steve.esm mod activated. esp version, or both at the same, none of them let the game load while they were ticked. Haven't found anyone else experiencing the same issue with Google, so I'm a bit at a loss.