Probablistic cause poses no problem for free will?

If someone could predict your action 99% of the time, do you still have free will?

It is conceivable that even if someone's action were predicted 100% of the time, that his action were free. For example, if Gary hates durians, and I predict 100% correctly that through his whole life he would choose an orange over a durian. Yet, his action was free.

But this is the case with only one particular action. What if every action of a person were predictable a 100% of the time. Suddenly, the person doesn't appear to have free will anymore; if we can predict a person's every action 100% of the time, it would have to be that his actions were caused by something known to us.

Let's seperate the implicit premises. If my prediction was by pure chance, and not based on some deterministic cause, it appears that 100% predictability of a person's every action and his having free will is not incompatible. Of course the chance of getting it 100% right is vanishingly small, but it is not impossible.

Yet, we believe that the chance is so small that it should be taken as being impossible. I believe that it cannot be taken as so. Probablistic cause is only an indicator that free will might not be present, but it is not incompatible with free will.