Apple says it’s determined that a small percentage of the keyboards in certain MacBook, MacBook Air, and MacBook Pro models may exhibit one or more of the following behaviors:
Letters or characters repeat unexpectedly
Letters or characters do not appear
Key(s) feel "sticky" or do not respond in a consistent manner
Apple or an Apple Authorized Service Provider will service eligible MacBook, MacBook Air, and MacBook Pro keyboards, free of charge. The type of service will be determined after the keyboard is examined and may involve the replacement of one or more keys or the whole keyboard.
To identify your computer's model and to see if it is eligible for this program, choose Apple () menu > About This Mac. Eligible models can be found by clicking here.