Windows 11 KB5120998 is resetting custom mouse cursors

Microsoft’s Windows release-health notes list the incident as “Microsoft has received reports of mouse customization settings being lost.” The company says affected users may see appearance settings changed or reverted, intermittent animation changes, larger white high-DPI cursors, or custom cursor animations returning to their defaults.

The reports concern KB5120998, an optional preview update released Aug. 27, 2026. Microsoft lists the affected client versions as Windows 11 version 24H2 and version 25H2. The corresponding builds are 26100.9278 for 24H2 and 26200.9278 for 25H2. No server versions are listed as affected.

The important bit is the wording. Microsoft acknowledges that users are reporting the problem, but it has not confirmed that KB5120998 is definitively the cause. Its current status is “Reported,” and the release-health entry says Microsoft is investigating whether the issue is caused by Microsoft, with an update to follow. That is a meaningful distinction: this is an acknowledged incident under investigation, not a confirmed root-cause announcement.

A cursor is small, but it is also one of the most constantly visible parts of Windows. Personalisation settings can be cosmetic, accessibility-related or both. A pointer that suddenly becomes oversized, white or difficult to distinguish is more than a minor annoyance, particularly on high-resolution displays or for people who rely on colour and scale adjustments.

Because KB5120998 is a preview update, it is not the same as an unavoidable monthly security fix. However, Microsoft’s release-health note does not currently tell users to uninstall it. Reports that removing the update restores cursor settings have circulated, but that remains a reported workaround from secondary coverage rather than official Microsoft advice. Treat rollback decisions carefully, especially if the update fixed another problem on your PC.

Microsoft is doing the right thing by documenting the reports quickly, but the cursor should not be treated like a mystery box after an update. Until the investigation produces a cause or fix, users on 24H2 and 25H2 should avoid installing optional previews unless they have a specific reason to test them. If your cursor has been rearranged by KB5120998, press Windows key + F to open Feedback Hub and submit a report, including your Windows version, build and what changed. That gives Microsoft useful evidence without pretending the case is already solved.