Microsoft: KB5120998 mouse reset bug affects only non-English PCs
Microsoft confirmed that an optional August 2026 preview update, KB5120998, causes mouse personalization settings to reset, but only on non-English Windows 11 systems.
Intelligence analysis by Gemini 2.5 Flash
The KB5120998 update, intended to bring Start menu, taskbar, and Windows search improvements, has been reported by users to automatically revert mouse cursor personalization settings. Microsoft's investigation revealed the issue is specific to code components in non-English Windows installations.
Imagine your computer is like a toy car, and you've picked out a special color for its steering wheel and a fun horn sound. A new update for the car comes out, but if your car was bought in a country that speaks a different language, the update accidentally makes your steering wheel go back to its plain old color and forgets your cool horn sound. It only happens to cars from those other countries, and the company is looking into why.
Analysis
The recently released KB5120998 August 2026 preview update for Windows 11 has introduced an unexpected bug that causes mouse personalization settings to revert to default configurations. This issue, initially reported by users, was subsequently confirmed by Microsoft, leading to an investigation into its root cause and scope. The update itself is optional and non-security related, focusing on enhancements to core Windows interface elements like the Start menu and taskbar for versions 25H2 and 24H2.
KB5120998
Microsoft's KB5120998 update was designed to deliver various improvements to the Windows 11 user experience, specifically targeting the Start menu, taskbar, and Windows search functionalities. However, shortly after its release on August 27, 2026, users began reporting that their customized mouse settings, including cursor appearance and animations, were being automatically reset. This created an inconvenience for those who had personalized their system, as the changes were not easily reversible once the bug manifested. The update's optional nature means users must actively choose to install it, unless the 'Get the latest updates as soon as they're available' option is enabled, which would lead to automatic installation.
Non-English Windows devices
A crucial finding from Microsoft's follow-up investigation, detailed in a Tuesday update to the Windows release health dashboard, is that the mouse reset bug is exclusively affecting non-English Windows 11 installations. The company attributed this specificity to "code components used in non-English Windows installations," explaining that in these impacted locales, the personalized settings fail to load correctly, causing the system to default to standard settings instead. This narrow scope helps Microsoft target a fix and provides clarity for users, indicating that English-language Windows systems are not susceptible to this particular issue.
Windows Recovery Environment
This is not the first instance of Microsoft addressing mouse-related issues on Windows devices. In recent months, the company has had to release several fixes for similar problems, demonstrating an ongoing challenge in maintaining peripheral compatibility and settings stability across its operating system. For example, emergency updates were deployed in October to resolve a critical issue that rendered the Windows Recovery Environment (WinRE) unusable by disabling USB mice and keyboards. More recently, Microsoft has also been investigating a bug where the mouse pointer disappears for some classic Outlook users when moved over the interface, and acknowledged that desktop settings might also be lost or reset after installing the KB5120998 preview update, further highlighting a pattern of configuration-related glitches.
Key points
- The KB5120998 August 2026 preview update causes mouse settings to reset.
- Microsoft confirmed the bug affects only non-English Windows 11 systems.
- The issue is attributed to specific code components in non-English Windows installations.
- KB5120998 is an optional, non-security update, but can install automatically if 'Get the latest updates' is enabled.
- Microsoft has addressed other mouse-related issues on Windows devices in recent months.
Microsoft has quickly identified the specific demographic affected by this bug (non-English PCs), which should streamline the development and deployment of a targeted fix. Since KB5120998 is an optional update, users can choose to defer installation, mitigating immediate impact, and Microsoft has a track record of resolving similar mouse-related issues.
Users with non-English Windows 11 installations who install the KB5120998 update will experience the annoyance of having their personalized mouse settings reset, potentially disrupting their workflow and requiring manual re-configuration. This could lead to frustration and a perception of instability in optional system updates.
