Suggestion : Firewall Learning Modes
Provided F-secure has checked and found no malware on the host pc, is it possible adding a Firewall Learning mode where the firewall allows all connections and applications while it's on Learning Mode and makes rules for them, you know, something like calibrating the network without having to troubleshoot what's wrong with a certain safe app not connecting or something else network related not working. ESET Smart Security has a feature like that, saves me the fuss of troubleshooting the network.
Since I mention ESET, they also have an interactive mode where every communication pops up an alert and you can create rules to allow or deny that communication. It's not automatic as Learning Mode but it still saves me time from going around blind and it still gives more than enough control over the network.