Is your main computer an Apple laptop? When you use it at home or in the office, are you one of those who connects an external mouse or the original Apple trackpad? Have you noticed that as soon as you connect the external element the built-in trackpad of the MacBook stops working? This is easy to fix.
This will be the only time that I put myself as an example: but in my case I work with a 13-inch MacBook Air from 2012. I have been working with it tirelessly for the last 7 years. And, yes, it is my main computer since then. I wanted a laptop because I usually take it anywhere I can preview content for you. But at home, however, I leave it on my work table and I connect, via Bluetooth, both an Apple Keyboard and the Magic Mouse.
Some time ago, and without knowing what had happened, when I used the Magic Mouse with the MacBook Air, the integrated trackpad stopped working; away from home it worked like a charm. The secret was in the settings. Exactly, I don't really know who touched the settings — surely in some misunderstanding of mine, my oldest son would haunt my work table and fiddle with the mouse and system preferences.
Either way, an option had been activated on my MacBook Air that rendered the laptop's built-in trackpad inoperative. what had happened? Well, an option had been activated in "System Preferences". More specifically, we had to access "Accessibility" and go down to the "Interaction" section. There, look for the section that refers to "Mouse and trackpad" and check that the option that indicates us is unchecked in the menu on the right "Bypassing the built-in trackpad in the presence of a wireless trackpad or mouse".
Of course, if you want it to stop working to avoid major scares - I'm still looking for the reason why I would check this option - leave the box as it was.