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Windows Update · reviewed KB record
KB5120998

August 27, 2026 Windows 11 preview update

An optional preview cumulative update that later appeared in release-health history for desktop-background and mouse-personalization regressions on affected systems.

Released: 2026-08-27Reviewed: 2026-09-17Type: Optional preview cumulative update

Release status

Released; documented personalization issues resolved by later update

Windows releases

Windows 11 25H2 · Windows 11 24H2

OS builds

25H2 — 26200.9278 · 24H2 — 26100.9278

Documented known-issue context

  • Some affected systems could lose or reset desktop background settings and show a solid black background.
  • Mouse cursor/customization settings could reset on some non-English Windows installations.

Later resolution or status change

  • Microsoft documents both the desktop-background and mouse-personalization issues as resolved by the September 8, 2026 update KB5124008 and later.
Interpretation rule

Do not infer causation from timing alone

An issue beginning after an update can still be caused by a driver, peripheral, application or hardware change. Use Microsoft’s documented affected platforms and issue state, then confirm the symptom matches.

Evidence

Microsoft sources reviewed

Update records preserve the source and review date because release-health status can change after publication.

Related authority records

Continue with the same failing system

These links share the same component or repair context; they are not generic keyword suggestions.

Windows updateKB5121003 — August 11, 2026 Windows 11 security update

The August 2026 security update for Windows 11 25H2 and 24H2. Release-health history links it to an ARM Teams/new Outlook launch issue, while a reported game-unresponsiveness cluster was later determined to be associated with RGB-related third-party drivers/components rather than Windows Update itself.

Windows updateKB5124008 — September 8, 2026 Windows 11 security update

The September 2026 security cumulative update for Windows 11 25H2 and 24H2. Its Microsoft support record documents several post-release issues and later resolution changes, which makes build and symptom matching important before troubleshooting.

Windows updateKB5129195 — September 14, 2026 Windows 11 out-of-band update

A cumulative out-of-band follow-up to the September security update. It is especially relevant when troubleshooting documented RDS instability, Plan9 host-folder sharing, or multichannel USB-audio failures introduced around the September update cycle.

Error0x80070002 — Windows Update error 0x80070002: what it means and what to try first

Microsoft groups 0x80070002 among update install failures; preserve the context before using broader repair steps.

Error0x80073712 — Windows Update error 0x80073712: component store inconsistent

Microsoft maps 0x80073712 to ERROR_SXS_COMPONENT_STORE_CORRUPT in the Windows servicing context.

Error0x800F081F — Windows Update error 0x800F081F: repair source missing

In Microsoft’s servicing guidance, 0x800F081F maps to CBS_E_SOURCE_MISSING and calls for component-store repair or a valid matching source.