Android Question Critical Issue: B4A blocked. Windows Defender says it has a virus.

See these two posts - It looks like Microsoft Defender released another new update that doesn't like B4A:

JohnC said:

See these two posts - It looks like Microsoft Defender released another new update that doesn't like B4A:

B4A.EXE Trojan:Win32/Bearfoos.A!ml ?

Today Microsoft Defender blocked my B4A.exe file with this warning: Any advice?

www.b4x.com

Bearfoos.A!ml in B4A.exe

Hello. This morning, when I try to run B4A, I received a warning from Windows Security: Nothing changed from yesterday. I don't have any antivirus software installed except the one included in the OS (Win 11). Anyone else with this issue? I'm using the latest B4A version. Looking on what...

www.b4x.com

Click to expand...

Thanks for the links, John. I reviewed both carefully, but unfortunately neither resolves the issue I’m facing.

The first one confirms that Microsoft Defender is flagging the latest B4A installer, which seems to be part of a broader compatibility issue. Even after temporarily disabling the antivirus, the official installer still fails to complete successfully on my system.

The second link shows that other users are experiencing similar problems with the current version, which reinforces the idea that this may be a recent conflict with Windows.

Thankfully, I was able to install an earlier version (13.3), which still works well on my setup. To help others who might be in the same situation, I’m preparing a simple download page with the installer available for direct access.

I truly appreciate your willingness to help. Let’s keep sharing insights as we work through this.

Hello everyone,

Since the latest version of B4A didn’t work for me either, I’m sharing the installer for version 13.1, which I was able to get working:

To prevent automated access, I added a simple verification step on the page (just a basic math challenge). It’s nothing fancy, but it helps protect the resource.

Note: I don’t have a professional hosting service, so the file may become unavailable if it gets too many downloads.

Best regards to all.

Download: B4A 13.1

Same problem here
Install B41 13.1 from the above post seems to work

Thanks for confirming, Adrian. I'm glad the installer worked for you!

Hopefully the issue with Defender will be fixed soon.

If anyone else needs the installer, please use the download page while it's available.

Installing an old version is a mistake.
I wasn't able to reproduce this false positive detection after installing all updates.

If the installer is blocked then you can right click on the executable file and choose Unblock.

Erel said:

Installing an old version is a mistake.
I wasn't able to reproduce this false positive detection after installing all updates.

If the installer is blocked then you can right click on the executable file and choose Unblock.

Click to expand...

Thank you, Erel, for your response and clarification.

I understand your position regarding the risks of installing older versions, and I agree that reverting should not be the first solution. However, in my case—and apparently in Adrian’s as well—the latest installer was completely blocked by Windows Defender, and the IDE failed to launch even after forcing the installation.

I suspect the reason this issue only affects a few users is due to the staggered nature of Windows Defender database updates. Not all systems receive the same definitions at the same time, which might explain why some installations succeed while others are flagged.

To better understand the situation, I ran the installer through several independent scanners. While VirusTotal shows no detections, Hybrid Analysis flagged it as Backdoor.Agent.mytozz.lgzu, and ScanWith reports that McAfee identified it as Malware.TR/AD.RiskWareTool.a. These results are not conclusive, but they do suggest that certain engines are reacting to something in the executable.

I’m sharing this not to challenge the integrity of the software, but to help clarify why some users might be experiencing unexpected blocks.

Thanks again for your continued support and development.