Microsoft has confirmed that a Windows 11 black desktop background is a real bug in its August optional update, and not something users did to their own PCs. The company added a new entry titled “Desktop background settings are lost or reset on some devices” to the Windows release health dashboard on 2 September 2026 at 18:29 PT, with the status listed as Confirmed. Until then, the complaints had been circulating only in user reports, with nothing on any Microsoft page.
What causes the Windows 11 black desktop background
The culprit is KB5120998, the optional preview update Microsoft released on 27 August 2026. According to Microsoft’s own entry, some Windows desktop settings fail to load after the update installs. The result is a desktop background that shows up as a solid black colour instead of your wallpaper.
Microsoft also warns that the damage may not stop at wallpapers. Its note says other desktop settings may be affected too, and names slideshow settings and contrast themes specifically. Contrast themes are an accessibility feature, so this is not purely cosmetic for everyone who hits it.
Both Windows 11 version 25H2 and version 24H2 are listed as affected. Windows Server is not. The dashboard records the originating update as OS Build 26100.9278, and prints that same build number on the 25H2 page as well as the 24H2 one.
There is no workaround yet
This is the uncomfortable part. Microsoft states plainly that you cannot fix it yourself by setting your wallpaper again, because the update stops the settings loading at all, whatever they are set to. In the dashboard’s words, on affected devices “attempting to manually restore customized settings does not work”.
Microsoft says it is working on a resolution for a future Windows update, and will share more when it has something. No date is attached to that. It has not said whether any particular upcoming update carries the fix.
That leaves affected users with nothing to do but wait, or remove an update they were invited to install in the first place. KB5120998 was an optional preview, not a mandatory security patch. Anyone who took it did so because Microsoft offered it as an optional item in Windows Update, and got a black desktop and no undo button for their trouble. If you want to roll it back, we walked through the uninstall path in our earlier report on the same update.
The cursor bug from the same update has firmed up too
KB5120998 already had a second problem on the dashboard. Mouse personalisation, including custom cursors and cursor animations, was reverting to standard settings. That entry has since moved to Confirmed as well, last updated 1 September at 18:55 PT.
Microsoft has scoped that one to code components used in non-English Windows installations, where the settings fail to load and a default gets used instead. That framing matters in India, where many PCs are set to a regional display language such as Hindi, Tamil or Bengali. The desktop background entry, by contrast, carries no locale statement at all — Microsoft refers only to affected Windows installations, without saying which ones those are.
What you should do now
- If you have not installed KB5120998: there is no reason to seek out an optional preview update with two confirmed bugs on it. Leave it alone and take the regular security update when it arrives.
- If your wallpaper has gone black: re-applying it will not help, per Microsoft. Uninstalling the update is the only lever you have.
- If you use a contrast theme: check that it is still applied, since Microsoft lists contrast themes among the settings that may be affected.
We will update this story when Microsoft names the update that fixes it.
