My case was that the Secondary Tap not working after upgrading to the new MacOS Mojave 10.14 even all is set correctly from the setting . How to fix?
Normally, just Reset the PRAM, and the issue gone.
How to reset the PRAM or NVRAM on Mac?
- Turn off your Mac.
- Press the power button to open it again
- Quickly press the Command , Option , P , and R keys at the same time Before the grey screen appears.
- Make sure you keep holding the keys until you hear the startup sound twice.
Notification: At for Macs with the T2 Security Chip, hold the keys until the Apple logo appears and disappears for the second time.
- Release the keys.
Trackpad then must work correctly.