IMPORTANT: Microsoft has patched the “Windows Firewall is using settings that may make your device unsafe” last year, but the increasing number of people reporting about this malfunction let us guess that Microsoft has changed some essential settings lately. If you prefer using third-party security tool, one of the solutions would be to turn off Windows Security Center Notifications. That's because third-party security tools activate their own Firewall pushing Windows Defender Firewall away. The bulk of Windows Firewall settings make your device unsafe error victims started getting this error after installation of third parties. Many people reported that the “Windows Firewall is using settings that may make your device unsafe” error started right after installing third-party antivirus (e.g., Emsisoft, ESET, Trend Micro, Avast). This may happen due to various reasons, for instance, installation of the latest Windows updates (e.g., 1607 or 1709). However, Windows Firewall is rather vulnerable and often fails to work properly or stops working entirely. Illustrating 'Windows Firewall is using settings that may make your device unsafe' Besides, it is capable of blocking certain types of traffic or log suspicious traffic. It's responsible for monitoring the outgoing network traffic and blocking unsolicited network traffic.

That's a big problem since Firewall is an essential player in keeping Windows OS protected.

The error indicates the fact that Windows Firewall was turned off and will not be turned on until the user changes its settings. What makes all of the Windows users that ran into this error is the fact that clicking the X button, which usually allows closing the message, redirects to a new pop-up saying “Restore settings.” However, clicking on it won't work either, except that UAC dialogue occurs and the warning remains. It contains a red X button, which once opens a new pop-up saying “Actions Needed.” Then the user is informed that GPO set Firewall off because it uses settings that may put the device at risk.

It is generated by Windows Actions Center or Windows Notifications Center in the form of a pop-up window. “Windows Firewall is using settings that may make your device unsafe” is an official alert generated by Windows OS. I'm quoting the content because the site has PUPs on the page so cannot be linked:

I would also ask this at our sister forums for IT Pro's Technet: I'm Greg, an installation specialist, 10 year Windows MVP, and Guardian Moderator here to help you.

Check avast firewall settings