I have a notebook running Ubuntu Mate and the trackpad stopped working after login (it worked on the login screen). This is what I did to fix it:
- Run
xinput
command on the terminal. - Copy the trackpad ID.
- Run
xinput --list-props [trackpad ID]
. - Check if
Synaptics Off
is set to 1. - If so, run
xinput --set-prop [trackpad ID] 'Synaptics Off' 0
Solution found on Ubuntu Ask.