Windows PCs missing key updates could lose security fixes in 2027

Microsoft is advising users and businesses to update Windows devices before digital certificates used to verify Windows Update servers expire in May and June 2027.

The certificates expire on May 17 or June 19, depending on the Windows version. Devices without replacement certificates will lose access to Windows Update, including security fixes delivered through the service. Microsoft is distributing the replacements through a process known as certificate rotation.

“However, the key to getting updates from Windows Update beyond 2027 is to keep your devices up to date today,” Microsoft’s Andrew Brown said.

Who needs to take action

Most users running a supported Windows version and installing monthly updates should receive the replacement certificates automatically. Some versions require action from IT administrators.

Supported systems that have fallen behind need the required security update. Microsoft advises users with unsupported versions to upgrade.

Windows 11 version 25H2 and later require no action. Version 24H2 needs the September 2025 security update or a later release. Several other supported versions need the July 2026 update or later.

What happens if the deadline is missed

Supported systems can regain access after the deadline by installing the required update. Administrators can download it from the Microsoft Update Catalog or distribute it through their management tools.

Devices receiving updates through Windows Server Update Services, or WSUS, are excluded from this change.