Everything would have turned out fine if ___ not there.

The correct choice in this context is "you're," which is a contraction of "you are." In the sentence "Everything would have turned out fine if you're not there," the intended meaning is to express that the outcome would be positive had the person in question not been present. Using "you're" signifies that it refers to the state of being present or not, aligning perfectly with the conditional structure of the sentence.

On the other hand, the other options do not fit the context due to their meanings. "Youre" is not a valid English word, "you'r" is an incorrect contraction as it lacks the necessary letter for proper contraction and thus does not convey any meaning, and "your" is a possessive adjective that indicates ownership but does not keep with the conditional structure necessary for this sentence. Hence, only "you're" accurately conveys the intended message in a grammatically correct manner.