Preview in windows explorer stops working after installing 2025-10 Cumulative Update for Windows 11 Version 24H2 for x64-based Systems (KB5066835) (26100.6899)

It seems that you are experiencing issues with the preview function in Windows Explorer after installing the 2025-10 Cumulative Update for Windows 11 Version 24H2 (KB5066835). This issue may be related to a bug introduced by the update. If uninstalling the update resolves the problem, it indicates that the update may be the cause of the malfunction.

As of now, there is no specific mention in the provided context regarding a fix for this particular issue. However, it is advisable to keep an eye on future updates or patches from Microsoft that may address this bug. You can also report this issue through the Feedback Hub app to help Microsoft identify and resolve the problem in future updates.

References:

• Resolved issues in Windows 11, version 24H2

Hi Marsha Burnette-Pierre

There's no bug, this is a deliberate change of this update:
https://support.microsoft.com/en-us/topic/october-14-2025-kb5066835-os-builds-26200-6899-and-26100-6899-1db237d8-9f3b-4218-9515-3e0a32729685

Right click one of those files and choose Properties.
If you see the Unblock button, they are affected.

To bulk unblock the files, open Powershell and type:

Unblock-Item -Path "pathtoyourfolder"