I'm having this problem as well. However, my computer can start without being plugged in sometimes. I brought my 2013 13" Macbook Air in, not even a year ago, for my backlight being out, and I swear Apple messed something up; my backlight was going out again a few months ago, and now this battery thing is happening. I wanna say loose connection, but I'm moving today, and I have absolutely no tools to check. Anybody with THIS case?Can you start up the Macbook using battery along? (e.g. with the magsafe unplugged)