One of the keys in keyboard has become "harder to press" I have a Retina MacBook Pro and I don't know how to explain it well. One of the keys (number 9 key, if it makes sense) has suddenly "not sensitive enough" while typing fast. I mean, I can definitely press it when I want, the change is very subtle, when I'm typing fast it doesn't get pressed. If I explicitly press just a bit harder there is no problem. Whenever I tap all keys with my typing pressure, all get pressed easily expect the 9 key. The difference is subtle but it's definitely noticeable and is really annoying while typing (especially when typing ( when programming). How do I make it respond normally?
The problem went away by itself in a few hours and never came back. Everything returned back to normal.