KB5066835: Overview with user sentiment and feedback
Last Updated October 19, 2025
Probability of successful installation and continued operation of the machine
Overview
October 14, 2025—KB5066835 (OS Builds 26200.6899 and 26100.6899) applies to Windows 11 versions 25H2, 24H2, 23H2, 22H2, and 21H2. This update addresses security issues for the Windows operating system and includes fixes and quality improvements from previous updates. It also enforces a security hardening improvement for RSA-based smart card certificates and updates AI components. Notably, it removes the ltmdm64.sys driver, which affects fax modem hardware. The update is set to prevent Windows Secure Boot certificate expiration starting in June 2026. Known issues include problems playing protected content in some BluRay/DVD/Digital TV apps and issues with IIS services.
General Purpose
The primary purpose of KB5066835 is to provide security updates to address vulnerabilities in the Windows operating system. It includes enhancements to security features, such as enforcing the use of Key Storage Provider (KSP) instead of Cryptographic Service Provider (CSP) for RSA-based smart card certificates. Additionally, it incorporates fixes for various issues reported in previous updates and updates AI components for better integration with Windows Copilot+ PCs.
General Sentiment
The general sentiment towards KB5066835 is mixed due to its dual nature of providing necessary security updates while introducing some issues. While the update is crucial for maintaining system security and includes several fixes and improvements, it has also been reported to cause problems with IIS services and playback of protected content in certain apps. Users who rely heavily on IIS or face issues with protected content playback may experience disruptions. However, for general users, the benefits of the security updates likely outweigh the drawbacks.
Known Issues
- Some Digital TV and Blu-ray/DVD apps may not play protected content correctly after installing this update.
- IIS services, including local hosted IIS and applications using HttpListener or System.ServiceModel.ServiceHost, may not function correctly after installation.
Disclaimer: We take measures to ensure that AI-generated content is of the highest possible quality, but we cannot guarantee its accuracy and recommend that users do their own independent research. Generated on 2025-10-19 01:17 AM
