Why would a new MacBook Pro charger fail in one month?

I've got a new MacBook Pro 15" that comes with the 87W USB-C adapter from US.

I live in Turkey and I've got all my MacBooks from US with US chargers, and had no issue with them (as they are meant to be used internationally anyway) for years.

It's been just one month since I've got my MacBook Pro. I don't know if it's relevant at all but yesterday we've tried connecting my MacBook Pro with my friend's MacBook over USB-C to transfer files (it didn't work, or we didn't know how to do it, but anyway) and my MacBook Pro started charging by draining my friend's MacBook's power. It was a 30 second thing, then we've disconnected them and I've charged/used by MacBook Pro for hours using the regular AC adapter for hours. Today it was charging perfectly at a coffee shop that I always visit (and charge my MacBook Pro). I came home and plugged it into the AC outlet that I also always use, but it didn't charge. It didn't even detect the charger (so it's not the "not charging" issue). I've tried my friend's charger and it works, I've tried my charger with my friend's MacBook but it doesn't charge either, so it's the adapter (we've also tested the USB-C cables by swapping, no effect, I've tried all the USB-C ports, no effect either). I've also tried SMC reset, no avail.

However, there is one interesting catch: MacBooks always have this subtle "shocking" effect when they are connected to the AC outlet if I rub my hand on the unibody (it's something that happens with every MacBook I've seen on every charger, on every venue/house regardless of the outlet). Even though the adapter appears totally dead, I'm still having this shocking effect, so some power is delivered to the MacBook even though it's not charging. I've charged my MacBook Pro to 100% using my friend's charger, then I plugged it out and plugged in the "dead" charger. I've left my MacBook Pro attached to the "dead" charger in sleep mode (by closing the lid as I always do), left for about 4 hours, then came back. It was at 50% charge, almost as if the charger drained by MacBook Pro's battery (it's impossible for it to go from 100% to 50% in sleep, obviously, and there aren't any background apps that prevent sleep). When attached to the charger, it was probably still "on" as it was somehow "detecting" the charger (though doesn't detect it as a power adapter/charger) and has been on for 4 hours doing nothing with a turned off LCD, thus draining half of the battery (again, this is just my assumption). I'll probably get a replacement charger, but I'm really interested in knowing what's going on here.

To summarize:

• No MacBooks are charging with a specific charger.
• It just happened out of blue (no power outages, no liquid spill, nothing extraordinary other than I've tried connecting my MacBook Pro to my friend's MacBook over USB-C, but I've used and charged my MacBook Pro for hours on the now-dead charger for hours afterwards).
• Even though it doesn't charge and doesn't detect the AC adapter in power reports, touching the unibody when the "dead" charger is connected still gives the "electric feeling", so there is at least something delivered.
• Leaving the "dead" charger connected to my Mac apparently prevents sleep.
• My MacBook Pro charges and powers perfectly with my friend's charger and my iPad charger (though they charge much more slowly because of much less power output).

What might be happening?

Solution 1:

What might be happening?

You have a defective charger. It's not unheard of and if you are a manufacturer of products, it's quite common. With every single product that is made around the world, there is a percentage that fail. This is called a defect percentage or rate.

The total number of defects counted on the population in question divided by the total population count.

At one point, Apple was expecting a 10% defect rate on iPhones made by Foxconn.¹

Does this mean that they are just going to let defects go? Of course not, but being that these are complex products dependent on the manufacturing processes of other vendors, defects are bound to show up. Even with the best QA processes in place, it's not perfect.

You received a charger that failed. This is why they offer you a warranty.

As for the electric feeling, this also is a common occurrence and has been discussed on this site:

• How can I avoid my MacBook Pro giving me minor shocks?
• Is it bad that my MacBook Air is passing me electricity?
• Avoiding electrical shocks/statics

Basically, it boils down to the adapter not being grounded/earthed and using a 3 prong plug (applicable to your country) solves the problem.

¹Apple Expected 10% Bad iPhones from Foxconn? Mark Graban's Lean Blog, May 6, 2013.

Solution 2:

Take it right back to Apple. Let them fix it and politely ask them what happened. Don't mess around with that much money. If you want to self-diagnose, hold down the power button for 15 seconds until you hear a chime and the light begins to blink slowly. This resets the PRAM.

USB ports on Macs are protected internally. If something goes wrong, they are disabled to protect them and the machine. I have a Canon camera that will crash the port if connected by a straight USB cable, but works fine with a cable that has a choke filter on it. The surge from plugging it in causes my Mac Pro to disable the port. Same thing with an external network adapter I bought.

Solution 3:

Because of the bathtub curve. Stuff is more likely to fail when it's very new or very old, so you should expect new stuff to be less reliable than moderately aged stuff.