Techdows published a story that Windows 10 KB4574727 update being blocked and flagged as Trojan by BitDefender.

Windows 10 KB4574727 Update being blocked and flagged as Trojan by BitDefender

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.

Windows 10 KB4574727 Update being blocked and flagged as Trojan by BitDefender