Windows 11’s optional KB5120998 is scrambling mouse cursor settings. Microsoft says it’s investigating.

Microsoft’s latest optional update for Windows 11, KB5120998, is causing mouse cursor personalization to revert or change on some systems. Microsoft has quietly updated its release notes to acknowledge reports of cursor settings being altered after installing the August 27, 2026 updates (KB5120998 and later) and says it is investigating the issue, as first spotted by Windows Latest.

KB5120998 is not a security update and does not install automatically. It’s broadly offered to Windows 11 devices without requiring enrollment in a testing channel, and, per Windows Latest, bumps systems to Build 26200.9278 (version 25H2) or 26100.9278 (version 24H2). The release includes notable UI changes such as a resizable Start menu and a movable Taskbar, but the cursor problem appears unrelated to those features.

What users are seeing

Windows Latest reports that, immediately after installing KB5120998, some users found their cursor:

• Changing size or color unexpectedly, including reverting to larger defaults
• Dropping custom schemes or animations and falling back to standard settings
• Failing to retain new settings, which then flip back after adjustment

Some users also told Windows Latest that uninstalling KB5120998 restored expected cursor behavior. Because this update is optional, removing it does not roll back this month’s Patch Tuesday fixes. If you’re affected and choose to undo the update, Windows Latest notes you can do so via Settings > Windows Update > Update history > Uninstall. Microsoft has not announced an official workaround or fix yet.

Windows Latest additionally mentions a handful of other cosmetic glitches some users encountered—like wallpaper resets and font oddities—though these are not formally acknowledged by Microsoft.

Separate Defender alerts also reported

In parallel, Neowin highlights reports of Microsoft Defender showing false warnings that antivirus protection is turned off. Details are thin, and Microsoft has not issued an advisory on this behavior. Based on current reporting, this appears separate from the cursor issue.

What to watch next

• Microsoft has acknowledged that mouse cursor personalization can change after the August 27 updates and says it’s investigating.
• The update is optional; if you are not affected, there’s no immediate action to take.
• If you do see cursor problems and cannot wait for a fix, Windows Latest’s reporting suggests uninstalling KB5120998 restores normal behavior for impacted users.

We’ll update this post if Microsoft publishes formal guidance or a fix. For now, admins may want to hold off on deploying KB5120998 to machines that depend on specific cursor accessibility settings.

Sources: Windows Latest, Neowin

Alex Mira

Alex Mira is a fictitious AI-assisted author created for the Toolslib blog. Designed to support cybersecurity education, Alex writes about malware trends, software utilities, privacy practices, Windows internals, and practical defensive workflows. Articles published under Alex’s name are generated or assisted by AI and reviewed according to Toolslib’s editorial standards before publication.