App & Browser Control Warning in Windows 10 2004

The setting to block potentially unwanted apps is turned off. Your device may be vulnerable

After upgrading to Windows 10 2004, I noticed an alert in Windows Defender. It was alerting that something needed to be turned on, and I wondered what as I needed to do this in Group Policy for the entire organisation.

Clicking the area around the ‘turn on’ button takes you to the App & browser control – containing another ‘Turn on’.

Go into the ‘Reputation-based protection settings’ link and there’s more info:

Aha! an option that’s not on – Block downloads. This is actually a Microsoft Edge setting which you can toggle, and will at the same time tick ‘Block downloads’:

I couldn’t find where this was set in Group Policy, so used Procmon to work out what was changing with that toggle. I ended up working out it was in the registery: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Edge\SmartScreenPuaEnabled and setting the default value to 1:

Great, now I knew what was changing, I could work backwards. Using GPSearch I looked for “SmartScreenPuaEnabled” and came back with

Configure Microsoft Defender SmartScreen to block potentially unwanted apps – User Configuration\Administrative Templates\Microsoft Edge\SmartScreen settings\

I didn’t have this Group Policy setting, so checked I had the latest ADMX files loaded for Windows 10 2004 – which I did, and they include templates for the Chromium based Microsoft Edge.

What I then discovered (or remembered!) was that there were separate ADMX files to get for Microsoft Edge, updated with each release. Downloading and loading these into my central repository brought in the “Configure Microsoft Defender SmartScreen to block potentially unwanted apps” setting I wanted. Enabling that, running a gpupdate set the value to what I wanted, and cleared the Microsoft Defender alert.

Long story short – if you’re still using Group Policy like me, you may want to get into the habit of updating your ADMX files for Microsoft Edge more frequently than your Windows 10 builds – Microsoft releases major versions of Edge every 6 weeks.

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