Windows 11 24H2 and 25H2 Updates Break IIS Websites After Patch Tuesday

Microsoft has confirmed that the latest Windows 11 24H2 and 25H2 updates are breaking IIS (Internet Information Services) websites following October’s Patch Tuesday release. The issue, caused by a conflict in the Windows HTTP stack driver (HTTP.sys), leads to “ERR_CONNECTION_RESET” errors when accessing localhost loopbacks or other IIS-based connections.

The problem affects devices running updates released on or after September 29, including KB5066835 and KB5065789. Microsoft, in an update to Windows Release Health Dashboard, explained that “server-side applications relying on HTTP.sys may experience issues with incoming connections,” resulting in failed IIS websites or blank pages. The bug affects localhost setups and developer environments.

The Redmond giant noted that the issue could appear under “a variety of conditions,” including differences in internet connectivity, system timing, or update installation order. That means not every Windows environment will encounter the same problem, but for those that do, it can disrupt internal testing setups and hosted web apps.

While the company confirmed it is working on a permanent fix, IT admins have been advised to apply a known issue rollback (KIR) via a special Group Policy configuration. The rollback effectively restores system stability by reversing the problematic changes without requiring a full uninstall of the update.

Microsoft shared a dedicated download link for Windows 11 24H2, 25H2, and Windows Server 2025 admins. The Group Policy package can be found under Computer Configuration > Administrative Templates after installation.

This update comes alongside better news, though. Microsoft has also removed an upgrade block on Windows 11 24H2 devices after resolving a third-party driver conflict that had been preventing installations.

via: Neowin