Chosen Solution
I’m trying to fix a family member’s 2015 MacBook Air, it’s having some strange problem where the trackpad tracks fine, but won’t register clicks (physical click or tap to click) and the UI doesn’t respond to the cursor hovering over elements like the dock or window buttons. It does this with the built in trackpad, and a USB mouse that I’ve tested in both USB ports. I’ve tried booting into safe mode and recovery mode, resetting the SMC and PRAM, and it still hasn’t fixed it. I have tried booting into this computer’s hard drive using target disk mode, and the trackpad works fine on my own 2012 MacBook Pro running on this Air’s hard drive. Both of the computers are running High Sierra. I first thought it was water damage, because the owner of this computer frequently uses it with wet hands, but the cursor moves fine, so I’m thinking it must be a software problem? This is a work-owned computer so I don’t want to need to open it up. Thank you!
You need to open it to see if the battery is swollen and pressing against the bottom of your trackpad. MacBook Air 13" Early 2015 Battery Replacement
