KB5120998 Triggers Mouse Cursor Problems for Windows 11 Users
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The KB5120998 mouse personalization issue is affecting some Windows 11 users after installing Microsoft’s optional August 2026 preview update.
Microsoft is investigating reports that customized mouse cursors and animations revert to their default settings after users install KB5120998.
Microsoft confirms mouse personalization problems
Microsoft acknowledged the issue on its Windows Release Health dashboard.
Affected users report that custom cursor settings disappear and Windows restores the default cursor configuration. Some users with high-DPI cursor settings also report seeing larger white cursors instead of their customized versions.
The issue affects Windows 11 24H2 and Windows 11 25H2 client editions. Windows Server does not appear to suffer from the problem.
Microsoft has not confirmed that KB5120998 directly causes the issue. The company continues to investigate the reports and determine the root cause.
Users also report black desktop wallpapers
Mouse settings are not the only problem users have noticed after installing the update.
Some Windows 11 users report that their desktop wallpaper changes to a solid black background after installing KB5120998.
Microsoft has not confirmed a connection between the update and the wallpaper problem.
The company is asking affected users to submit reports through the Feedback Hub so engineers can collect more diagnostic information.
Microsoft Defender is also showing false warnings
Microsoft is separately investigating incorrect Microsoft Defender notifications.
The notification claims that “Microsoft Defender Antivirus is turned off” even when the antivirus remains enabled and working.
Some users reportedly receive the warning after every Windows restart. Others say the notification can continue appearing even after they disable related notifications.
Microsoft says this issue affects supported client and server editions of Windows 10 and Windows 11. The company has acknowledged the bug but has not released a fix yet.
As for other recent Windows update problems, Microsoft has concluded that RGB software is responsible for crashes linked to KB5121003.
Via Neowin
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