Due to a file corruption or some reason I started getting below error
AppArmor enabled on system but the docker-default profile could not be loaded: strconv.Atoi: parsing "found": invalid syntax
I followed below steps to fix this problem. Please take backup of AppArmor profiles if you created any before running below commands
sudo rm -rf /etc/apparmor*
sudo apt remove --assume-yes --purge apparmor
sudo apt install apparmor
I think https://docs.docker.com/engine/security/apparmor/ provides some indication of the issues with using apparmor and docker.