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.

Windows Security has reputation-based protection that can help protect your PC from potentially unwanted applications. Potentially unwanted app blocking was first introduced in the Windows 10 May 2020 update and is turned on by default for enterprise customers, but off by default for consumers.

The Program Install and Uninstall troubleshooter helps you automatically repair issues when you're blocked from installing or removing programs. It also fixes corrupted registry keys. First, you'll need to download the troubleshooter. Download troubleshooter. If you see the File Download box when you start downloading, select Run or Open.

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.

Windows 10. Use controlled folder access. Controlled folder access in Windows Security reviews the apps that can make changes to files in protected folders and blocks unauthorized or unsafe apps from accessing or changing files in those folders. Select Start > Settings > Update & Security > Windows Security > Virus & threat protection.

See threats that have been quarantined before they can affect you and anything identified as a threat that you have allowed to run on your device. Note: If you are using third-party antivirus software, you’ll be able to use its virus and threat protection options here.

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.

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.

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.

Learn more at Getting started with Microsoft Defender. Windows 10 or 11 in S mode. Some features will be a little different if you're running Windows 10 or 11 in S mode. Because this mode is streamlined for tighter security, the Virus & threat protection area has fewer options.