With the battery out, plug the computer in and turn it back on. Look for signs of swelling, which can push up on the trackpad mechanism from below and cause it to behave erratically. If not, use a coin to twist the battery release knob and lift the battery out. Run your hand over the bottom to see if the battery casing is lying flush with the rest of the computer base. Turn the computer off and flip it over to check your MacBook's battery for signs of swelling, which can happen over time, particularly important if you're using an older laptop.

If you occasionally use a mouse, deselect the box next to 'Ignore trackpad when mouse is present.' Close the 'Keyboard & Mouse' window and see if the trackpad problems are resolved. Under Trackpad Options, click the box that instructs the MacBook to ignore accidental trackpad input. Deselect the options under Trackpad Gestures to see if it resolves the problem. Look at the tracking speed and double-click speed sliders to ensure that the pointer is set somewhere in the middle, between the Slow and Fast options. Click on the 'Keyboard and Mouse' option and select the 'Trackpad' tab to access trackpad settings. Click on the Apple menu and click 'System Preferences' from the drop-down menu.

Mac trackpad issues