August 27, 2026—KB5120998 (OS Builds 26200.9278 and 26100.9278) Preview

Microsoft released the optional Windows 11 25H2 and 24H2 preview update KB5120998 with new management, File Explorer, Windows Share and interface improvements.

What changed

KB5120998 updates Windows 11 25H2 to build 26200.9278 and Windows 11 24H2 to build 26100.9278. It introduces modernized progress indicators, improves File Explorer Home performance, adds suggested work or school apps to Windows Share and makes Administrator protection available as an opt-in control through Microsoft Intune OMA-URI or Group Policy.

Technical details

File Explorer Home opens faster and the Recommended carousel supports touch scrolling
Startup, sign-in, restart, shutdown and update installation use updated progress indicators
Windows Share can suggest relevant apps for users signed in with a work or school account
Administrator protection can be enabled through Microsoft Intune OMA-URI or Group Policy and remains disabled by default

Why it matters

The preview exposes upcoming Windows behavior and policy controls before broad production rollout, allowing endpoint teams to validate management settings, user experience and application compatibility on representative devices.

Known limitations

Microsoft maintains the current known-issue and rollout status in the linked KB article

Now check

Pilot KB5120998 on representative Windows 11 24H2 and 25H2 devices
Validate builds 26100.9278 and 26200.9278 plus File Explorer, Windows Share and sign-in behavior
Review Administrator protection policy requirements before enabling the opt-in control