this is a somewhat creative answer that diverges slightly from the authors intent
The machine oredictspredicts that in five years it shall malfunction due to a flaw in its design. When this occurs, the machine will only do what maximizes the greatest happiness for the scientist. As a result, the humans will blissfully and blindly live under a complete accidental dictator. Everyone will be blind to the transition. The scientist wont be aware of the change so as to not be unhappy and hence the glitch remains unforseenunforeseen. Everyone is happy and living well. However, they are put into extreme poverty almost like lemmings.
On another note in a different direction, a machine like this might just need so much power that the energy reserves will be depleted im six months of running the machine. The best option is to shut it off indefinitely. This is believable considering the nature of the simulations.