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.
Release status
Released; several reported issues later resolved or reclassified
Windows 11 25H2 · Windows 11 24H2
25H2 — 26200.9168 · 24H2 — 26100.9168
Documented known-issue context
- On some ARM-based devices, Microsoft Teams and the new Outlook could fail to launch or close unexpectedly after August security updates, especially on new/fresh images without current Store updates.
- Some game crashes reported after this update were investigated and attributed to RGB-related peripheral/internal-device drivers or components rather than the Windows update itself.
Later resolution or status change
- Microsoft documents the ARM Teams/new Outlook issue as resolved by KB5124008 on September 8, 2026 and later.
- The game-unresponsiveness issue is recorded as resolved/reclassified after Microsoft identified the third-party RGB driver/component relationship.
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.
Microsoft sources reviewed
Update records preserve the source and review date because release-health status can change after publication.