Does it drive you crazy when you are using a USB wireless mouse and when you type anything, the trackpad is actively moving your cursor around causing havoc with your documents? This is how you can turn this off and save you a great deal of frustration.
Open System Preferences by selecting the Apple menu at the top-left and then select “System Preferences.”
For me, it makes sense to put the option to turn off your trackpad either in the Mouse or Trackpad options, but it is not located in either place. Go ahead and select “Accessibility” at the bottom. Next and to the left, select “Mouse & Trackpad.” If you want to turn off your trackpad when using an external mouse, such as corded or wireless, place a checkmark in the box: Ignore built-in trackpad when mouse or wireless trackpad is present. Voilà! That’s it. You can test this as soon as you checkmark the box. It works magnificently.
If you need to make other adjustments to your mouse or trackpad, you can go back to System Preferences and individually, select the Mouse or Trackpad to customize your settings for each.
For more than 15 years, Scott Lindsay has helped thousands of people better their skills, publishing more than 500 articles about Apple and Microsoft software, the computer and the Internet. You can reach Scott for comments or questions at ScottLindsay@live.com.