Are USB-C Docks Killing M1 MacBooks?

Several M1 MacBooks have reportedly died while using third-party USB-C docks.

You probably use (or plan to use) a dongle or adaptor with your M1 MacBook. There have been reports recently that some of these USB-C adaptors have been killing M1 MacBooks. In this article we’re going to be investigating this issue and telling you if you need to be worried or not.

A quick rundown on USB-C

USB-C is a very versatile port – functional in 2 orientations (no more trying to insert your USB-A devices in the wrong way), while also having the potential for increased bandwidth, courtesy of the higher number of contacts in the port.

USB-C can also be extended through systems such as PCI-E (which is a protocol designed to communicate with devices such as GPUs, network cards, SSDs, etc.) to create “Thunderbolt” ports.

These are more versatile than USB-C, and at least two ports have featured in every MacBook since 2018 (with the first being found in the 2015 12-inch Retina MacBook). This allowed Apple to simplify the design, while still allowing all the connectivity of older MacBooks – but with one major caveat: adapters.

Apple’s 12-inch MacBook

These adapters are a necessary evil. They add additional connectivity to the existing USB-C ports – like HDMI ports, gigabit ethernet (via a gigabit ethernet port), and even standard USB-A ports.

USB-C, like any other port relies on a protocol. This can be thought of like a language that is needed to communicate with the CPU, for the device to do its job.

This protocol must be supported by the operating system (in this case macOS) for any devices that are connected to function properly. Due to the amount that USB-C can be extended (from charging your computer, to providing a display output for two 4K monitors), there is a special “packet” which is sent to the computer to tell what the devices connected to the hub are able to do.

This is where the importance of a quality USB-C hub is important, as more affordable (i.e. cheap) docks often are not as reliable at pushing this packet. This is most dangerous when dealing with anything that draws power.

What is the actual issue?

macOS first sends out a “packet” message to the charger, to determine what wattage the charger is (i.e. 40W, 60W, 100W, etc.), so macOS’ built-in power management system can monitor and manage the charging to help reduce battery wear.

When a USB-C power pass-through is used (i.e. a power adapter is plugged into a hub, which is then plugged into a MacBook), this packet may not match the specification of the charger, and overdraw power (e.g. a 60W charger is rated as an 80W charger, and therefore is out of specification). This causes a lot of stress to the adapter, and the charger. 

There have been reports of this overload causing the adapter to eventually fail, and in some cases short the circuit boards present inside the MacBook.

This eventually also causes consistent kernel failures, as macOS essentially overloads all the components. This can cause vital components such as your CPU or SSD to fail, therefore “bricking” your machine.

Apple can replace this component, however – it’s expensive if you’re not covered under some kind of warranty. Also, if you don’t have a recent backup, you can say goodbye to any important documents or data that was on your MacBook.

A similar issue can be found with devices that draw power from the MacBook itself, such as USB devices and displays.

As the hub is not able to display the proper power draw needed, macOS tries to supply too much power to the hub, which runs a significant risk of damaging the USB-C port, the hub and the device that is receiving the power.

This can quickly turn into a big problem with devices such as an expensive 4K monitor, as you have the potential to lose thousands of dollars worth of equipment. If power is going both in the hub via a charger, and out to other devices for a long time, it may cause the hub to overheat, which has the potential to damage the MacBook and the port it is connected to. 

MacBook thunderbolt port
Your best option to avoid this issue is to simply attach your charger directly to your MacBook (source: Cult of Mac)

What can you do to avoid this?

To prevent this happening to your MacBook, there are 2 different approaches that you can take.

The first is simple – use a good quality hub from a reputable brand. I would recommend anything that Apple sells themselves (or any other brands that can be found on their store). If you’re on a budget but still want a relatively high-quality hub, check out the Anker 8-in-1 hub which we’ve reviewed previously.

By using a high-quality USB-C hub, you’re able to guarantee that this packet exchange is going to be as reliable as possible, while also being able to claim any potential damage on warranty (depending on the hub and manufacturer).

Alternatively, consider a proper dock – like the CalDigit TS4. I use this in addition to my Anker USB-C hub and haven’t had any issues so far.

The second, and more straightforward way to prevent this issue from affecting you is to simply plug your charger directly into the computer.

This allows for the MacBook to skip the “middleman” (the hub), which results in more reliable charging. However, again, you should use the official charger that came with the MacBook in the box, or one from a reputable manufacturer.

With the release of the latest macOS Big Sur updates, it is confirmed that there have been revisions to the way macOS receives packets related to charging. As always, it is highly recommended to keep your Mac updated to avoid any potential damage to your MacBook.

MacBook USB-C Hub Charging FAQ

What charger should I use to charge my MacBook?

It’s best to use the official Apple charger that came in the box with your MacBook. It is specifically designed to safely and effectively charge your specific model of MacBook. However, you can also use chargers from different brands. Just ensure that the brand is well-known and produces good quality products. Anker, Belkin, Dell, and CalDigit are some examples.

Is it safe to charge my MacBook with a USB-C hub?

Generally it is safe to charge your MacBook using a USB-C hub. It’s always recommended to use official Apple hubs or chargers where possible, but you can also use good-quality accessories from well-known brands if you prefer. If you’re worried about the hub potentially damaging your MacBook, you can simply attach your charger directly to the MacBook instead of the hub.

Will a USB-C hub damage my MacBook?

Generally not, as long as you are using a good-quality hub from a reputable brand like Dell, Anker, or OWC. If you’re worried however, you can attach your charger directly to your MacBook instead of the hub when you need to charge.

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