If you’ve got one of those fancy new Macbooks with the USB-C charging cable, Apple is ready to replace it for you if it’s one of the defective ones.
“A limited number of Apple USB-C charge cables that were included with MacBook computers through June 2015 may fail due to a design issue,” says the Apple web page announcing the program.
Your MacBook might not charge (or only charge intermittently) when it’s connected to one of these faulty cables.