Recently Windows Vista has been refusing to show the Windows Firewall Settings dialog box and instead showing the ever so informative message: “Windows Firewall: Due to an unidentified problem, Windows cannot display Windows Firewall settings”.

No clues. Nothing in the Event Log. Nothing. Brilliant.

Well I had a brain wave this morning about what might be causing it. Thankfully it turned out to be right. I remembered that on our Windows Domain we have a few Group Policy settings that apply to Windows Firewall.

In this case the culprit was the “Define program exceptions” that had a few old entries for AVG 7.5 Network Edition. As we’d upgraded to AVG 8.0 recently the program paths were no longer valid, nor really necessary. So I removed them entirely and set the policy back to Not configured. To verify it worked I ran gpupdate /target:computer /force at a command prompt on my workstation and voila: the Windows Firewall Settings dialog box would now appear once more.

 

Group Policy for Windows Firewall is stored on client machines in the the Registry at:

HKEY_LOCAL_MACHINESOFTWAREPoliciesMicrosoftWindowsFirewall

So if you’re not on a domain and there are registry entries in this location that have been set for some reason, then adjusting them will have the same effect as changing the Group Policy. If you are on a domain then getting the Group Policy fixed is obviously the right approach.

Hope that helps you – leave a comment if it does.