One of the most intriguing new features in Windows 10 version 1709 is a security setting that prevents unauthorized apps from gaining access to Windows system files and your personal data files.
With the Controlled Folder Access feature turned on, malicious and suspicious apps are blocked from changing files in known locations. That's a major roadblock for most known strains of ransomware, which do their dirty work by encrypting your personal files and demanding payment for the decryption key.
If you want to use this feature, you have to jump through a few hoops to turn it on. By default, it's available in all Windows 10 editions but is off by default.
In addition, you must have Windows Defender real-time protection enabled. In this release, the Controlled Folder Access feature does not work with third-party antivirus software.
With those prerequisites out of the way, open Windows Defender Security Center. Click Virus & threat protection > Virus & threat protection settings and toggle the switch under Controlled folder access to On, as shown above.
That's all the configuration that's required. But you can adjust the default settings using the two links beneath that:
Click Protected folders to display a list of the folders whose contents are currently being protected from tampering by a malicious or suspicious app. The default list includes data folders from the current user profile and from the Public profile.
Click Allow an app through Controlled folder access to manage a list of whitelisted apps. Most well-known apps are already whitelisted, but you can add a program to the list if you see a Controlled Folder Access error message from that app and know that it's safe and trustworthy.
At any time, you can turn the feature off by going back to Windows Defender Security Center and toggling the Controlled folder access switch to the Off position.
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