Laptop touchpad stops working randomly on Ubuntu 18.04

Update: Changing touchpad from advanced to basic (through BIOS), and installing i2c-tools helped fix my issue. Thread regarding the same here.

I had a similar problem. For me, usually I could restore it by Suspend then log in again, which is less disruptive than a full restart, so I set the power button to Suspend so this would be easier.

As for cause and prevention, it will vary by device, but I just discovered that my touchpad is set up with a "features" that disables it with a double-tap in a particular corner. Usually, mine disables when the fan changes speed while my finger is touching the touchpad, so I'm guessing that something about the fan motion makes the device think I double-tapped that corner. I'm looking in to how to disable that "feature".

I've seen other posts talking about static etc from the fan interfering with their touchpad - there might be something similar with yours.