Microsoft KB5120998 Preview Update Resets Mouse Settings on Non‑English Windows 11 PCs
What Happened — The optional August 2026 preview update KB5120998 for Windows 11 (versions 25H2 and 24H2) automatically reverts mouse cursor personalization settings to defaults. The issue is limited to non‑English language installations, where the locale‑specific code fails to load the saved configuration.
Why It Matters for Trust & Control Assurance
- Demonstrates the risk of unvetted software changes slipping into production environments, a scenario continuous control‑assurance programs are built to detect and document.
- Highlights the need for change‑management evidence (baseline configurations, post‑update validation) to satisfy audit requirements across frameworks.
- Aligns with Verisq’s Control Mapping capability, which helps organizations map such configuration‑drift incidents to control objectives and collect defensible evidence.
Who Is Affected — End‑user devices running Windows 11 in non‑English locales; primarily enterprise desktops and laptops across all industries.
Recommended Actions
- Pause deployment of KB5120998 on non‑English systems until Microsoft releases a fix.
- Use a formal change‑control process: capture pre‑update configuration baselines, apply the update in a test group, and verify settings post‑install.
- Enable continuous monitoring of configuration drift and retain logs as audit evidence.
Technical Notes — The bug stems from locale‑specific code components that fail to load saved mouse settings, causing Windows to fall back to default cursor options. It is an optional, non‑security preview update; no CVE is associated. Source: BleepingComputer