If you want to confirm that PUA blocking is turned on for your device see Protect your PC from potentially unwanted applications. This app has been blocked. Microsoft Defender SmartScreen has the ability to block potentially unwanted apps before they're installed and if that happens you'll see a blocked event in the Protection History.

Fix problems that block programs from being installed or removed. Windows 10 Windows 8.1 Windows 8 Windows 7. Note: Use these steps for Windows programs. If you're having problems with an app you got from Microsoft Store, go to Fix problems with apps from Microsoft Store.

There are two ways to allow an app through Windows Defender Firewall. Both of them are risky: Add an app to the list of allowed apps (less risky). Open a port (more risky). When you open a port in Windows Defender Firewall you allow traffic into or out of your device, as though you drilled a hole in the firewall.

Select Start , then open Settings . Under Privacy & security , select Windows Security > Firewall & network protection . Open Windows Security settings. Select a network profile: Domain network, Private network, or Public network. Under Microsoft Defender Firewall, switch the setting to On.

The settings on the App & browser control page let you: Block unrecognized apps, files, malicious sites, downloads, and web content. Set up warnings for unrecognized apps, files, malicious sites, downloads, and web content. Turn off blocking and warnings altogether.

The Protection History page in the Windows Security app is where you can go to view actions that Microsoft Defender Antivirus has taken on your behalf, Potentially Unwanted Apps that have been removed, or key services that are turned off. Note: Protection History only retains events for two weeks, after which they'll disappear from this page.

This app has been blocked for your protection. Administrator has blocked you from running this app. When you are attempting to run an application and it gets blocked by Smart Screen because the signature is no longer valid and now lists Publisher: Unknown. The application will not open.