A recent batch of Microsoft’s optional updates has left some Windows 11 users facing a frustrating problem. The KB5120998 August 2026 preview update, designed to bring various improvements such as enhanced Start menu and taskbar functionality, has been found to reset desktop settings on affected devices.
Specifically, the bug is affecting systems running Windows 11 versions 24H2 and 25H2, causing wallpaper changes, including automatic switching to a black background. Furthermore, other desktop settings like slideshow configurations or contrast themes may also be impacted. As a result, users are unable to restore their custom settings on affected devices.
Microsoft has acknowledged the issue in a recent Windows release health update, stating that following the installation of the KB5120998 update and later releases, some Windows Desktop settings fail to load, leading to a solid black color being displayed as the desktop background. The company also notes that attempting to manually restore customized settings does not work due to the bug preventing correct setting loading.
In related news, Microsoft has acknowledged another issue with the same KB5120998 update, where it resets mouse settings and makes it impossible for affected users to restore their previous settings after they are reverted. This problem was first reported by Bleeping Computer on September 2, 2026. While this bug only affects non-English language PCs, it’s yet another example of the potential risks associated with installing optional updates.
Microsoft has a history of addressing similar bugs in its updates. For instance, in February 2020, the company acknowledged an issue with the KB4539602 update that broke desktop wallpaper functionality for Windows 7 users in ‘Stretch’ mode, causing them to display a blank black screen.
For users who have already installed the KB5120998 update and are experiencing issues, Microsoft recommends checking their settings manually. However, given the severity of the problem, it’s not surprising that many users are seeking alternative solutions. To avoid encountering similar problems in the future, we recommend exercising caution when installing optional updates, especially if they’re not strictly necessary for security purposes.
In our experience, many users rely on automated update installations without carefully reviewing their contents. While this can save time and effort, it also increases the risk of encountering unforeseen consequences like the one described above. By taking a more proactive approach to updating your Windows device, you’ll be better equipped to identify potential issues before they cause problems.
Source: Bleeping Computer — 2026-09-03