Macbook Air 11" (Mid 2013). My girlfriends MBA has had a weird charging problem. We can never tell if it's going to charge or not. Attach the Magsafe and it charges, disconnect, and then no charge for hours, days, we just never know. For the last week, when we connect the adapter it doesn't work. Then last night when we went to the Apple store and it was charging fine, and the Genius' couldn't really help. The only advice they gave was that it might be dusty, so they dusted the port. The problem has been on and off. She has 3 different adapters, bought from Apple, but that doesn't seem to be the problem, they all work when the MBA is accepting a charge. We had the charging port replaced by an authorized dealer, and seemed to work fine, until a week later. I've troubleshooted everything I can think of (resets, playing with finicky cords, adapters, or power outlets, etc) and have tried everything I could, scouring the web, but I can't seem to pinpoint the problem. We thought maybe it was the temperature of the MBA or the power adapter, but it's showed the same results hot or cold. There are several articles on the web about this, and seems to work for a lot of people. One unique thing that I've noticed is that, when we attach the magsafe, we won't see a light, but if we open the screen (or turn on the computer, if it has a charge) then the light shows up on the charger. This has worked a couple times, but a few times it hasn't. Not a solid pattern, but might shed some light on what's wrong. I consider myself pretty good at troubleshooting, but this has got me perplexed. Any suggestions would be great. Thanks guys.