Microsoft Edge blocks and flags Firefox installer as Harmful

Image about Microsoft Edge blocks and flags Firefox installer as Harmful

Some users have reported Microsoft Edge is blocking all versions of Firefox Installer such as release, beta, dev, and nightly when attempted to download.
Edge says Firefox installer.exe was blocked because it could harm your device.

In case you don’t know:

  • Chrome uses Safe Browsing technology to protect users from malicious websites and files.
  • Microsoft Edge uses SmartScreen for the same
  • Both browser vendors use their technologies on Google and Bing search engines to warn users against malware.

More on Microsoft Defender SmartScreen Protection in Edge

Microsoft Defender SmartScreen in Edge analyzes the files downloaded by users against a known list of files

If it comes across an app or app installer not well known or commonly downloaded by users, it blocks the file download and shows a warning.

The protection is enabled by default at Settings > Privacy, search and Services > “Microsoft Defender SmartScreen”

Edge even offers an optional feature to block Potentially unwanted program downloads.

You can turn it on by toggling the “block potentially unwanted apps” setting.

Microsoft has also integrated PUA protection into Windows 10 from version 2004.

Microsoft Edge blocks Firefox installer

Coming to the article, in the Firefox case, according to Reddit threads [1] [2], a number of users confirmed Edge is warning when they download Firefox saying the installer could harm their device.

You can see the warning shown by Edge from Downloads Flyout in the screenshot above.

Firefox installer.exe was blocked because it could harm your device“.

Some affected users said they successfully downloaded and installed Firefox after disabling Microsoft Defender SmartScreen.

We’re not able to reproduce this for any Firefox version. The false-positive may have been fixed from the server-side by Microsoft.

The irony is disabling the Defender SmartScreen setting made Edge falsely trigger Firefox download as unsafe.

We expect that’s normal. Chrome will do the same when you turn off Safe browsing.

Read: Beware! Chrome/Chromium Edge flags downloads as harmful if you turn off this Security Setting

If you’re facing the issue right now, it’s unwise or not recommended to turn off Smartscreen, instead, use another browser to download Firefox or another app you have an issue with downloading from Edge.

By now, the Firefox download blocking on Edge may have been lifted.

In fact, once Bing flagged popular VLC Player as dangerous in the past, after a short time, the red flag was removed

What’s your take on this? Let us know in the comments below.