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I have a MacBook Air 13" High Sierra, early 2015. The computer is only a year old. Battery life is good, amperage good, holding a charge. The problem is, the very instant I unplug the Magsafe adapter it shuts down. Goes black. Dead. I've reset the SMC to no avail. I'm attaching images to show that the battery is indeed fine. Before I take this to the Apple store I thought I would check in with this bright, enlightened community.