When I find my car keys

Question

Hola 😊I translated the above as Cuando me encuentre las llaves. I was marked wrong, the answer is said to lack the "me". I think without the "me" they could be anybody's keys. Am I wrong?

Accepted Answer

Hola Dawn
In this specific sentence, it wouldn't be natural to use the pronoun because "encontrarse algo" generally means that you find something as a surprise/ by chance.
See this lesson here for different uses of encontrar/encontrarse. 
In this case it is obvious that the person is actively looking for the keys: "cuando encuentre las llaves". This doesn't mean that it's somebody else's keys. We actually use the definite article (el, la, los, las) to refer to things that are obviously ours - no need to use anything that expresses the possession. 
I hope it clarifies it.
Saludos