Is your Trackpad haywire? Going all over the place?
Mine was too. And I didn’t feel like replacing it–I just wanted to plug in an external mouse and turn the trackpad OFF.
There was just one problem–There was no setting in “System Preferences” –> “Trackpad” to do this!
BUT THE SETTING DOES EXIST!
Do This, it works. IT’S EASY. Go To “System Preference”, THEN “Accessibility”. (It’s there, LOOK under the “System” Category).
Click “Ignore Built-in Trackpad when Mouse or External Trackpad is plugged in”
There you go! The Possessed Trackpad is no more (as long as your mouse is plugged in).