Before assuming the system is broken, check if the error is actually triggered by a syntax issue in your configuration file that the current version of pfctl cannot parse. sudo pfctl -vnf /etc/pf.conf
A system update was interrupted, or only the kernel was updated without updating the rest of the base system. pf configuration incompatible with pf program version
System libraries that pfctl relies on were updated to a version incompatible with the running kernel. Before assuming the system is broken, check if
The command-line tool you use to load rules from /etc/pf.conf into the kernel. Before assuming the system is broken
You compiled a custom kernel with a different PF version than the one installed in your /sbin directory.
Use the to roll back to a known working configuration.