One of the cumulative updates released by Microsoft via Patch Tuesday September September 2020 on Windows 10 devices is incorrectly identified by Bitdefender as a potential threat.
The cumulative update KB4574727 released by Microsoft on September 8 for Windows 10 versions 1903 and 1909, focuses on resolving vulnerabilities in the operating system.
According to Microsoft itself, this update included security enhancements for key features in Windows 10, but also for peripherals such as mice, keyboards, and pens.
In essence, KB4574727 is an important security update, and it is obviously recommended that you install it immediately because it fixes vulnerabilities in the Microsoft operating system.
However, some users have found the installation of the update on their devices due to Bitdefender software. The protection engine mistakenly recognized KB4574727 as a potential threat, and while the update could be downloaded through Windows Update, the protection application blocked the installation.
Bitdefender software displays the following error on affected Windows 10 devices:
The file \ Device \ HarddiskVolume4 \ WINDOWS \ SoftwareDistribution \ Download \ 021b4073b65a625a58c006858ea0a97d \ Windows10.0-KB4574727-x64.cab is infected with Trojan.Ciusky.Gen.13. The threat has been successfully blocked, your device is safe.
The easiest way to fix this problem is to add an exception to this Windows update to avoid isolating files from Bitdefender's protection engine.
Other users tried to download the update from the Microsoft Update Catalog and attempted a manual installation with the same results.
Of course we expect Bitdefender to update the app to remove the false positive that appears on Windows 10 devices.