MacBook Pro: Some keys not working (correctly) anymore On my brother's MacBook Pro, suddenly the Enter, right shift, and right alt keys do not work properly anymore. It works with an external keyboard, though. PRAM/SMC reset did not help. Strangely, at least the shift and alt keys seem to at least work mechanically: When I press shift and a key, both inputs are completely ignored. When I press e.g. shift/alt/a, the correct special character is printed. So at least shift/alt seem to work, but only in some circumstances.

Any ideas on how to solve this?
Working correctly with an external keyboard is a good indicator that the internal keyboard is damaged and needs repair or replacement.