Bug Far Cry 3

(i bought the game on ubisoft connect if that helps) I start playing the game and when I get to the part after you throw the rock to distract the guard very early on the game crashes and I lose all my progress. I thought it was a one time thing but its happened multiple times ive retried at the same exact spot. I cant play the game cause I lose all my progress and it makes me restart and the same thing happens. What do I do?