This has been a problem.. Was doing this in 20.1 as well, a couple of people posted (including me) about how to resolve it and received no responses. I have NetFlow turned off.. With NetFlow off, the firewall hangs up on reboot with the following when shutting down for at least a minute:
Cannot 'stop' flowd_aggregate. Set flowd_aggregate_enable to YES in /etc/rc.conf or use 'onestop' instead of 'stop'.
How do I resolve this when not using NetFlow?
Netflow is likely not your problem, if flowd_aggregate_enable is set to "NO" it wasn't started in the first place.
You can easily check if the aggregator has an issue by checking the local process list "ps fax | grep flowd_aggregate" on a console.
I expect our rc.d cleanup doesn't check if the service is actually used, which means it would tell it can't stop it when not configured, usually not something to worry about.
Best regards,
Ad