This lock does not attach properly at all. I just purchased my 13"mbp early June of this year along with two of these locks so I could have one on the go and one with me for travel. This lock has two stubs of metal on both sides of the actual lock that attaches to the computer and all those things do is scratch the aluminum off of your computer! The rubber surrounding these parts may be helpful if the actual lock could even fit into the port- which it does not. Obviously the port and lock are not compatible on the 2011 models of the 13' mpb. The head of the lock is absolutely flimsy and is very weak, anyone could rip the cable out if they wanted to. I highly doubt that this is just a faulty lock because I tried both locks and they both did not fit. As for the port on my mpb, there is no "door" so I'm not sure what other people are talking about (yes I know which port is for the lock). Also, this lock partially blocks the edge of the cd drive and is very close to scratching the disk. Honestly apple, either improve this port, associate yourselves with a different lock, or make your own! This lock is HORRENDOUS.