If you are getting and error message saying "Failed to engage firewall" or a Firewall Violation (includes Security Error 0):
If your computer is institutionally managed by your employer, school, or other organization, you will likely not be able to use this computer with Exam4 if you've received this messsage.
Make sure your Windows firewall is turned ON, then run Exam4 again.
If you cannot turn the Windows firewall on:
1 . You may have a 3rd-party security application or 3rd-party firewall installed. (There are no known issues with Windows Defender.)
Use this article from the FAQ to remove the software and re-install Exam4 (which may have been damaged by the software)
2. Your computer may have been affected by a virus which has impacted your Windows Firewall settings.
Exam4 needs to engage the Windows Firewall, but if it has been altered by a virus, Exam4 is unable to do so. If you cannot engage the Windows firewall, you will need to either restore your computer to a time when it was working or have your operating system reinstalled so that it can be turned on.
If your computer is a Windows 10 machine, you can also try Microsoft's FixIt tool. http://support.microsoft.com/mats/windows_firewall_diagnostic/.