Apple has launched a replacement program for the USB-C cable that came bundled with 2015 Retina MacBook units, finding that some cables were faulty. Bad cables would result in the MacBook not charging, or charging unreliably when connected to a power adapter.
From Apple’s help site, affected customers can order a free replacement USB-C cable. Retina MacBook owners who provided a mailing address at product registration will be shipped a new cable automatically by the end of February … If you did not provide this information when buying the MacBook, visit Apple’s site to order a replacement cable instead …
You can tell if you are affected by looking at the printing on the side of your Apple USB-C cable. If the cable lacks a serial number next to the ‘Designed by Apple in California Assembled in China’ text, you should be eligible for a replacement. See the image below for a comparison of the affected and redesigned cables. Please note that although these are the graphics Apple provides, they appear to have made a Photoshop mistake with the ends — the photos depict Lightning cables, not USB-C connectors.
The replacement process can be initiated at an Apple Store with a Genius Bar appointment, at an authorized reseller or online via Apple Support channels. The program runs through June 8, 2018 so you have a couple of years to get your cables swapped out. If you can’t reach an Apple Store, it may be simpler to just buy a USB-C cable from a third party; I recommend the Anker USB-C cables which include additional reinforcement to prevent fraying, and will likely last longer than Apple’s first-party offerings.
Redesigned cables (identifiable by inclusion of serial number):