I have a macbook pro 2011. After an update I've been having problems with my left click not working. Thought it could be the trackpad going bad but I tried plugging an external mouse and the left click still didnt work. The right click works and if i try to drag the mouse around it will have the drag box and highlight anything I go over. I should also not this only happens when I plug in my laptop to charge at work. I took it to a repair shop and told them what was happening. They tried to get the issue to happen but it wouldn't happen. The left clicked worked fine. MAKES NO SENSE. So I they told me to take it back to work and try a different charger. I did that and the LEFT CLICKED STOPPED WORKING AGAIN. I dont get it. I seems to only be happening when I plug in my charger at work. I tried it with two different chargers and the same issue. Any one have any idea whats going on? It would be a great help. I am running latest version of OS X.