Let me preface this with the fact that I tried booting in checking and unchecking silent click in settings, restarted, shut down and rebooted, making a guest account, booting in safe mode, resetting NVRAM and resetting SMC. None of those things worked.
What finally did work was deleting the preference file (.plist) file in the preferences folder. This is the file that stores your settings for the trackpad. To accomplish this, do the following:
- From the OS X Finder, hit Command+Shift+G to bring up “Go To Folder”
- Enter the following path: ~/Library/Preferences/ and choose Go
- Locate the following files manually, or use the Search box in the upper right corner and narrow down for ‘driver’ to find them – remove the ones that are relevant to your issue:
com.apple.driver.AppleBluetoothMultitouch.trackpad.plist - Magic Trackpad
com.apple.driver.AppleBluetoothMultitouch.mouse.plist - Magic Mouse
com.apple.driver.AppleHIDMouse.plist - wired USB mouse
com.apple.AppleMultitouchTrackpad.plist
com.apple.preference.trackpad.plist
Now just reboot. With a reboot the Mac will rebuild the preference files for the input devices that are in use, and, hopefully at least, the erroneous tracking or clicking behavior will be resolved.
Remember, by ditching the preference files you’l lose customizations made to things like tracking speed, alt-click, gestures, and clicking behavior, so you’ll want to go back to the appropriate System Preference panel and reconfigure any specifics you had beforehand.