KB5066780: Fixed PowerShell Remoting and Windows Remote Management (WinRM).

October 14, 2025—KB5066780 (OS Build 25398.1913)

Improvements
This security update contains fixes and quality improvements from KB5065425 (released September 9, 2025). The following summary outlines key issues addressed by this update. Also, included are available new features. The bold text within the brackets indicates the item or area of the change.

• [Input]

1. Fixed: An issue where some characters didn’t display correctly when using the Chinese Input Method Editor (IME).
2. Fixed: This update addresses an issue where certain Chinese characters appeared as empty boxes in some text fields, such as those used in Connection Manager Administration Kit, when a character limit was set.​​​​​​​

• [Networking (known issue)] Fixed: This update addresses an issue where you might not be able to connect to shared files and folders if you're using the Server Message Block (SMB) v1 protocol on NetBIOS over TCP/IP NetBIOS (NetBT). This can happen after installing update KB5065425.
• [PowerShell] Fixed: This update addresses that affects PowerShell Remoting and Windows Remote Management (WinRM). Commands might time out after 10 minutes. ​​​​​​​
• [Stability issue] This update addresses an issue observed in rare cases after installing the May 2025 security update and subsequent updates causing devices to experience stability issues. Some devices became unresponsive and stopped responding in specific scenarios.
• [Compatibility] This update removes the ltmdm64.sys driver. Fax modem hardware dependent on this specific driver will no longer work in Windows.

If you've already installed previous updates, your device will download and install only the new updates included in this package.