If the left mouse button for your Apple computer stops working or suddenly becomes non responsive for no apparent reason, try this trick to possibly fix the problem.
- Using the right mouse button, navigate from the Apple (icon) menu to System Preferences and click on Mouse.
- Under “Primary mouse button” switch to the Right mouse button and then switch back to the Left. Try this a couple times (keeping in mind that the alternate button will be primary), and return to Left as the primary (or your preferred button).
This may restore the proper function of the left mouse button.