Non-English installations cause the KB5120998 cursor reset on Windows 11 (September 3, 2026)
Chapters
The cause Microsoft published
Microsoft's 24H2 known issues page, where this entry has been open since 15:36 PT on August 28, 2026, now states: "Our investigation indicates that this issue is caused by code components used in non-English Windows installations." It continues: "In impacted locales, these settings will fail to load, causing a default to be used instead." Both lines are on Microsoft Learn, against originating update OS build 26100.9278, KB5120998, released August 27, 2026.
This is a cause, not a cure. It tells you whether you are exposed and why the obvious remedy fails. It does not change what is available to do about it, and Microsoft has published no fix date with it.
TL;DR
Microsoft has named the cause of the cursor reset that arrived with KB5120998 on Windows 11: code components used in non-English Windows installations, published on its release health dashboard and reported by Windows Latest on September 3, 2026. In impacted locales the mouse settings fail to load, so a default is used, which is why reapplying them does nothing. No fix had shipped as of September 3, 2026, and uninstalling the optional update is still the only lever.
- Microsoft's wording: "Our investigation indicates that this issue is caused by code components used in non-English Windows installations."
- In impacted locales the settings fail to load, causing a default to be used instead, so manual restoration cannot work.
- Windows Latest reads the boundary as wider than display language: anyone with a secondary language or an additional keyboard layout installed appears exposed.
- The known issue has been open since 15:36 PT on August 28, 2026, and traces to OS build 26100.9278, KB5120998, released August 27, 2026.
- Uninstalling KB5120998 costs the preview features it carried, including the movable taskbar, the resizable Start menu and the decluttered Search box.
Who counts as a non-English installation
Microsoft's phrase is non-English Windows installations, which sounds like display language. Windows Latest notes the bug likely extends to anyone with secondary languages or additional keyboard layouts installed, which is a much larger group than people running Windows in another language. That reading is the outlet's, not Microsoft's wording, so treat it as the wider boundary to test against rather than a published fact.
You can see what your own machine carries in Settings, then Time and language, then Language and region, which lists every installed language and the keyboard layouts attached to each one. On that reading, one extra layout added years ago for a single document is enough to put you in the group.
The desktop half, on the same day
The other KB5120998 failure, desktop backgrounds turning solid black, was acknowledged the previous evening, and BleepingComputer carried Microsoft's wording at 08:16 AM on September 3, 2026 under Sergiu Gatlan's byline: following installation of Windows updates released August 27, 2026, KB5120998, and later, some Windows Desktop settings fail to load, resulting in desktop backgrounds displaying as a solid black color. BleepingComputer also notes the same update resets mouse settings on non-English PCs and that those settings are likewise unrestorable, on Windows 11 24H2 and 25H2.
Windows Latest's piece the same day still described the wallpaper reset as the unacknowledged one, which is what an entry opened at 18:29 PT the previous evening looks like in the following morning's coverage. As of September 3, 2026 the confirmed list is the cursor reset, the desktop background reset and the Arm based Teams and new Outlook launch failures. I covered the cursor half the day its entry opened, in the August 28 post.
Do not try to restore the settings by hand
Microsoft is explicit: "Attempting to manually restore the settings values is not successful, as the issue prevents loading these settings regardless of their value." A cursor scheme you pick again in Mouse Properties is stored and then ignored.
That is also the test for whether you are looking at this bug or something else. Set a cursor scheme, apply it, and watch the pointer. If it does not change, or it changes and will not hold, the load path is the problem and no amount of re-picking will fix it. Microsoft's line is that the restore attempt cannot succeed, so treat a pointer that will not stay put as this issue rather than as something you configured wrongly.
What you can do today
1. Check your language and keyboard list first, in Settings, then Time and language, then Language and region. That decides whether the published cause applies to you.
2. Stop re-applying cursor settings. Microsoft says the values cannot load, so this is time spent for nothing.
3. If the pointer matters more than the new preview features, remove the update: Settings, then Windows Update, then Update history, then Uninstall updates, select KB5120998, then reboot. In its August 28, 2026 piece, Windows Latest listed what that costs: the movable taskbar, the resizable Start menu and the decluttered Search box.
4. If you have not installed it, hold off while both issues are open. A Microsoft engineer quoted by Windows Latest on August 28, 2026 said the update is optional and that skipping it means the same changes arrive in the next mandatory update anyway.
5. Watch the known issue on Microsoft Learn for the resolved date. As of September 3, 2026 there is no fixing build published for either half of KB5120998.