If you have Windows 11 and installed the optional update KB5120998, you've probably noticed something wrong with your mouse or wallpaper. Microsoft has officially confirmed that this patch, released on August 27 as a preview of the new features coming in September, is causing customization issues on some computers. The bug affects both the cursor's appearance and configured animations, and in more severe cases, the desktop has also turned black or fonts have become blurry.
Microsoft has acknowledged the problem and is investigating the cause, but has yet to offer a definitive solution. The most frustrating aspect is that, in many cases, manually restoring the previous configuration is futile. This has led many users to question whether these optional updates, which often bring more problems than benefits, are even worth installing.
What exactly is wrong with the cursor and the wallpaper?
According to reports, update KB5120998 automatically modifies or resets cursor customization settings. For example, a high-resolution cursor might be replaced with the generic version, but larger. Custom animations also revert to their defaults, and the system does not allow users to restore their previous settings. This intermittent behavior has been reported by several users, although it is not a widespread bug.
In addition to the cursor issue, Microsoft has confirmed that the same patch causes the desktop background to reset on every boot or randomly, sometimes even displaying a completely black screen. The problem isn't with the saved value, but with how that configuration is loaded: the system can't read it correctly and applies a black background by default. This prevents the custom image from being set and also affects features like slideshows and high-contrast themes.
Some users have also reported issues with fonts, which appear blurry or less sharp than usual. While Microsoft hasn't officially confirmed this, numerous user reports suggest it could be related to the same update.
What's new in KB5120998 and why is caution recommended?
It's not all bad news. Update KB5120998 brings the system up to build 26200.9278 and introduces some of the most anticipated features of Windows 11, such as the ability to move the taskbar anywhere on the screen, a resizable Start menu , and a search function that no longer requires Bing. It also includes improvements to the Start menu, taskbar, and search bar, as well as changes to icon sizes.
However, Microsoft warns that these optional updates haven't undergone the same validation process as official releases, so they may contain bugs. The company recommends caution before installing them, especially if you're unwilling to take any risks. While the cursor issue isn't as severe as the October 2025 bug that rendered USB keyboards and mice unusable, it's still a significant inconvenience for those who rely on a specific configuration.
How to uninstall KB5120998 while waiting for a solution
If you've already installed the update and are experiencing these problems, the practical solution for now is to uninstall it. Since it's an optional update, you can remove it from Settings > Windows Update > Update history > Uninstall updates, locate KB5120998, and click Uninstall. Then restart your computer for the change to take effect. Affected users have confirmed that removing the package may restore the cursor and background to their previous behavior.
Microsoft is investigating the bug and has time to fix it before these changes are rolled out more widely with Patch Tuesday on September 8, 2026. In the meantime, the recommendation is clear: if you don't need the new features, it's best to wait and not install optional updates. Distrust of Windows Update is nothing new, and this incident serves as a reminder of why many users prefer to pause Windows 11 updates until it's confirmed they don't break anything.
In short, the KB5120998 update has once again highlighted that Windows updates can be a double-edged sword. On the one hand, they bring interesting improvements; on the other, they can break settings you've spent years configuring. Until Microsoft releases a definitive patch, the safest option is to uninstall it and wait. Trust in the operating system is built with each update, and incidents like this don't help.
