Bitdefender antivirus is blocking Windows 10 PC/laptops from downloading Microsoft’s KB4574727 patch


Bitdefender anti-virus red flags Microsoft’s Windows 10 KB4574727 cumulative update patch as a potential threat

If you have the Bitdefender anti-virus software on your Windows 10 PC/laptop you may have noticed that it is blocking Windows 10 KB4574727 patch from downloading into your PC/laptop. KB4574727 patch is one of the cumulative updates released by Microsoft as part of the September 2020 Patch Tuesday rolled out on 8th September for Windows 10 1903 and 1909 version run devices.

The irony of the Bitdefender antivirus tool blocking the Windows 10 KB4574727 patch is the patch itself is about resolving security vulnerabilities in the Windows 10 operating system and the built-in components. Microsoft in the KB4574727 bulletin says that the patch includes security improvements for basic operations in Windows 10 and accessories, like mice, keyboards, and pens. Microsoft adds that the KB4574727 patch also provides stability to the Microsoft Office productivity suite.

The KB4574727 was released on 8th September but as soon as it was released, Windows 10 forum was filled with queries about why their PC/laptops were not being updated. Many of these users found out that the installation of the KB4574727 patch was blocked by Bitdefender anti-virus products installed on their Windows 10 PC/laptop/server.

Apparently, Bitdefender’s antivirus engine mistakenly flags KB4574727 as a potential threat. The stranger thing is that Bitdefender lets the Windows 10 PC/laptop to download the update from Microsoft servers but blocks it right when the device is restarted to complete the installation process. This way the Windows 10 users who have Bitdefender installed are caught between the devil and the deep sea.

Some users reported that their Windows 10 PC/laptop booted back to the earlier version without the update being installed but many stated that they had to reboot the PC/laptop in order to get it started.

Bitdefender antivirus tool displays the following error on the affected Windows 10 devices:

The file \Device\HarddiskVolume4\WINDOWS\SoftwareDistribution\Download\021b4073b65a625a58c006858ea0a97d\ is infected with Trojan.Ciusky.Gen.13. The threat has been successfully blocked, your device is safe.

The easiest workaround to this problem is to whitelist the Windows 10 KB4574727 patch in the Bitdefender anti-virus tool settings. However, some users have also reported that even after whitelisting the Windows 10 KB4574727 patch, their machine flags the update as a potential threat.


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