Butterfly keyboard

The "butterfly" keyboard was a mechanism that was introduced as a feature of the Retina MacBook in 2015, the MacBook Pro in 2016, and the MacBook Air in 2018. However, it was prone to problems and was replaced by the Magic Keyboard, starting in November 2019, and completely phased out by May 2020.

Design
The butterfly keyboard was fitted with a two-sided hinged keyboard switch somewhat resembling butterfly wings. Pressing a key causes the hinge to flex downwards, where the key strikes a stainless steel switch dome.

The butterfly keyboard's design was significantly thinner than a scissor-switch keyboard, which features two interlocking plastic pieces and was used on Apple's previous keyboards. According to Apple, the butterfly keyboard was 34% thinner than previous MacBook keyboards and 40% thinner than the traditional scissor-switch design as a whole. The reduced height also improved travel time and altered the feel and sound of the keys.

Butterfly keyboards manufactured for 2018 and 2019 MacBook models included a membrane between the key cap and switch to protect the switches from debris. 2019 MacBook models were also equipped with covers atop the dome switches for further shielding.

Hardware problems
Despite Apple's initial claim that the butterfly keyboard was "four times more stable" than its predecessor, the thinner design offered less protection against foreign objects such as dust and debris. When dust became trapped under a key, the key could begin repeating, get stuck, or not work. The keyboard was also significantly more fragile: removing a keycap would often damage the clips securing it to the hinges, preventing it from being reattached (thus preventing users from attempting to clean or repair their keyboards).

Apple began redesigning the keyboard as early as 2016 to protect against such hardware issues. The July 2018 MacBook Pro models were manufactured with a membrane between the keycap and switch; while the company publicly stated that it was to reduce noise when typing, internal documents indicated it was meant to protect the keyboard mechanisms from dust. Tests showed that while the membrane offered more protection, foreign objects could still enter the keyboard through gaps in the membrane and lead to malfunctions.

In 2018, Apple began offering free keyboard repairs to all users who had purchased a device with a butterfly keyboard. The service program was valid for four years from the sale of the device.

Attempts to protect the keyboard mechanisms from debris and reinforce the hardware were largely unsuccessful. By 2019, Apple began transitioning its keyboards back to the scissor-switch design, which had significantly fewer hardware issues.

Legal settlement
In July 2022, Apple agreed to settle a lawsuit from dissatisfied customers for a total of up to 50 million. Individual users can get reimbursed from $50 to $395, depending on the level of issues encountered. Customers who had to pay out-of-pocket to fix problems related to butterfly keyboards had until March 6, 2023 to file a claim.