Chosen Solution
The trackpad no longer works in my mid-2012 Airbook. I opened it up and the battery doesn’t appear to be swollen. How much swelling does it take to impede Trackpad action? Is it generally visible when it occurs?
To test it remove the battery, here how: MacBook Air 11" Mid 2012 Battery Replacement Then boot with the Mag-Safe adapter plugged in. Try the trackpad. Also there were EFI trackpad updates. They usually get installed when you update your operating system.
