Hate to go there, but the Ghostbusters "Reboot" of 2016. My reasons is simple-it was poorly written, made to coddle one particular type of "fan", and did nothing to add to the franchise as a whole among many other things.
In short, it could've had potential had they kept it within the actual franchise and not done what they had done wit it. I mean the poorly received "Aliens vs. Predator" and "Alien Prequel" movies at least tried to fit into the established materials.
Sorry, kind of protective of one of my childhood favorite movies ;)