As part of Patch Tuesday, Microsoft released Windows 10 Cumulative Updates KB4571756, KB4574727, and KB4570333 for versions 2004, 1903 and 1909 and 1803. Apparently, BitDefender Antivirus is reportedly flagging KB4574727 as a Trojan “Trojan.Ciusky.Gen.13” and thus, preventing the Windows 10 Septemeber update installation.
The issue has been reported by affected users on Answers and BitDefender forums and on social media sites. Generally, users rely on Windows Update to download and install Cumulative Updates. If they face any issue while downloading or installing the update, they visit Microsoft Update Catalog for manual download.
Windows Update downloads the cumulative Update to the Software Distribution folder and installs the update after that. BitDefender is blocking update installation by flagging download as Trojan.
My Antivirus said that this update KB4574727 had a Trojan in it so it is in Quarantine. i have Bitdefender Total Security. I am going to uninstall the update because I’m not sure what else to do.
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.
One user reported on the BitDefender forum confirms installing the update manually by downloading from the Microsoft Update catalog also produces the same result.
Definitely, this is a false alarm from BitDefender Total Security. According to reports, some users went on to uninstall the update following the threat detection.
Do you use BitDefender? Are you affected? Let us know in the comments below.
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Encountered same issue, so I paused updates yesterday. But after updating BitDefender today, and then trying to update Windows, it allowed Windows to update.
Great to know that.
Another reason not to use antivirus, it’s a total waste of resources and money.
I am experiencing the same kind of KB4574727 update install issues on my Windows 10 zVersion 1903 build 18362.1016 system. However, I’m using Webroot SecureAnywhere version 9.0.29.51. I’m not exactly sure how it works, but Webroot uses a lightweight client on Windows 10 system but references common virus/trojan signatures back at a Webroot datacenter. So, I don’t think that updating my Webroot client will help me.
I tried downloading and installing the offline update for KB4574727 but it failed too.
Anyone have an idea of how I move past this?