Microsoft acknowledges desktop setting resets after August 2026 preview update

Microsoft confirmed that the KB5120998 preview update slated for August 2026 can cause desktop configuration settings to disappear or revert to defaults on certain Windows devices.

The update, part of the Windows Insider program’s monthly preview cycle, is intended to introduce security enhancements and feature refinements ahead of the final release. As a preview, it is distributed to volunteers who test upcoming changes before they reach the broader Windows user base.

Reports emerging from users who installed the update describe a range of visual changes, including loss of custom wallpapers, altered task‑bar layouts, and displaced desktop icons. In some cases, the changes persist after a system restart, effectively resetting the personalized environment that users have configured over time.

Microsoft’s statement acknowledges the problem and attributes it to an unintended interaction between the update’s configuration scripts and the system’s profile management. Desktop settings are normally stored in the user’s profile and applied at login; a misapplied registry change can cause Windows to reload default values instead.

To mitigate the impact, the company advises affected users to back up their settings using built‑in tools such as the “Export desktop settings” feature or to create a system restore point before applying future preview builds. IT administrators are also urged to test the update in controlled environments before wider deployment.

The incident highlights ongoing challenges in delivering frequent, incremental updates while preserving a stable user experience. Similar setbacks have occurred in past Windows releases, prompting Microsoft to refine its testing pipelines and improve rollback mechanisms.

Microsoft says a corrective patch will be issued in an upcoming cumulative update, though no specific release date has been provided. The company continues to monitor feedback channels and will provide further guidance as the issue is resolved.