I recently got home and plugged my iPhone 5S into my computer with a lightning cable I had found a few months ago on the street. The thing looked brand new and like it was in perfect working order, however, when I plugged my iPhone 5S into the computer with it it gave me a warning message on the screen saying "This cable is not supported by this device and may not work correctly" or something like that. Should I avoid using the lightning cable I found? I always like having at least two cables (one to plug into my computer and take on the go and one for my nightstand to plug the phone in at night), but I don't want any damage coming to my new phone. What do you guys think?