I had some charging issues with Lenovo X1 carbon. When I connect to charger, it doesn't charge.I did the following step to fix the charging problem according to a trouleshooting post. I disabled the built-in battery & reconnected AC adapter. But I cannot charge my laptop via AC adapter, so I cannot turn it on now. What fixed this issue was a trick suggested by nathan at geek squad tech support. I changed the power cable and everything is working fine now.