Microsoft has confirmed that the Windows 11 KB5066835 update is causing several issues, including a bug that blocks localhost connections and problems with the File Explorer preview pane.
The update, which is mandatory for Windows 11 versions 24H2 and 25H2, has introduced several new features, such as the ability to move on-screen volume indicators and a faster-loading context menu in File Explorer.
I use localhost all the time to debug my React apps, and after I installed the update, I found that I can no longer connect to 127.0.0.1.
Author's summary: Microsoft confirms Windows 11 update issues.