Microsoft Issues September Patch to Restore Lost Mouse Settings on Windows 11

Microsoft announced that its September 2026 update resolves a problem that caused mouse configuration settings to revert to defaults on certain Windows 11 devices after the installation of the KB5120998 preview released in August.

The issue, first highlighted by security‑focused outlet BleepingComputer, affected users who noticed their cursor speed, scroll behavior, and button assignments disappearing after applying the August preview. The regression was traced to a conflict between the preview’s driver handling routine and the operating system’s personalization registry entries.

Microsoft’s engineering team responded by incorporating a corrective fix into the regular September cumulative update for Windows 11. The patch restores the affected registry keys and adds additional validation to prevent similar resets in future preview builds. Users are advised to run Windows Update and install the latest September package to reinstate their preferred mouse settings.

Custom mouse configurations are a common accessibility and productivity feature, especially for professionals who rely on precise pointer behavior. While the glitch did not compromise system security, the unexpected loss of personalization sparked frustration among power users and raised concerns about the reliability of preview releases that precede broader rollouts.

Microsoft has reiterated its commitment to testing preview updates more rigorously before public distribution. The company’s Windows Insider program, which supplies early builds to volunteers, will now include an expanded validation suite targeting peripheral settings. This move aims to catch regressions like the mouse‑reset bug before they reach the mainstream update channel.

Going forward, Microsoft encourages anyone who experienced the issue to verify that their device is fully updated and to report any lingering anomalies through the Feedback Hub. Analysts suggest that swift remediation helps maintain confidence in Windows 11’s update cadence, a crucial factor as the operating system continues to mature beyond its initial launch period.