This may not be the best way. However, this method has worked for me.
- Here we are reinstalling ufw. This is to ensure all the files exist on the machine so we can fully reset ufw in the next step.
sudo apt-get install ufw
- Here we are fully removing and purging any files created by UFW
sudo apt-get remove --purge ufw
- Here we are installing ufw, this will recreate new files.
sudo apt-get install ufw
Your ufw firewall should now be reset to defaults.