As the title suggests, my Macbook Pro 2017 is switching itself off when I unplug it, and then won't switch back on. It usually starts behaving normally again within 24 hours, often less, but it's very aggravating as I have had the laptop for about a month. I took it in for a genius bar appointment and naturally the fault didn't occur during my visit and they could find no hardware problems. I've not spilled water on it or done anything else weird. The Apple people said that it sounded like a power surge, but I don't know why my computer would falsely think there was a power surge every time I unplugged it.