Patch intelligence record
Windows 11 25H2 (Build 26200.9278)
Current reports mention update/install failure, unspecified windows issue, and bsod / stop error. This page covers one cumulative update, not the whole 25H2 servicing train; reports about a later update are counted on that update's own page.
Recommendations
- Pause updates if this machine is doing deadline-sensitive or production work.
- Check Microsoft's known-issue and safeguard-hold list for this KB before installing.
- Keep the uninstall path in mind: a cumulative update can be removed from Settings > Windows Update > Update history for a limited window after installation.
Current reports mention update/install failure in windows update, unspecified windows issue in Windows workflow, bsod / stop error in system stability.
Too few reports for a firm verdict yet — treat this as early evidence.
- Accepted reports
- 7
- Latest evidence run
- Oct 6, 2026
- Healthy sources
- 2 fresh (success / no reports) · need 2
- Microsoft Q&A (search) Completed last checked Oct 6, 2026
- techcommunity windows sitemap Completed last checked Oct 6, 2026
Monitoring reflects community-evidence collection health for this exact release — an absence of reports is not a safety guarantee, and this is separate from the AUXSAYS verdict.
Vendor Known Issues — 1 active vendor-known issue
1 active 4 resolved
Official vendor Release Health status. Not counted as community reports. Official source ↗
Official Patch Notes — vendor release notes captured from the official source
Windows 11 25H2 cumulative update, OS build 26200.9278 (KB5120998). Released 2026-08-27 on the General Availability Channel. Update type 2026-08 D. This is the official Microsoft Windows release-health entry (learn.microsoft.com/windows/release-health). Known-issue and safeguard-hold details are published on the per-version Windows release-health status page. Microsoft Release Health status (official) for Windows 11.
Windows 11 in these notes: .
Windows 11 25H2 cumulative update, OS build 26200.9278 (KB5120998). Released 2026-08-27 on the General Availability Channel. Update type 2026-08 D. This is the official Microsoft Windows release-health entry (learn.microsoft.com/windows/release-health). Known-issue and safeguard-hold details are published on the per-version Windows release-health status page.
Technical Details
- Released
- Aug 27, 2026
- File size
- Official source checked
- Oct 6, 2026
- Official notes checked
- Oct 6, 2026
Checksum
Use these hashes to verify downloaded installers match the files published with the official release.
User Reports / Sources (7)
User report sources used for the current read.
- Microsoft Learn Q&A. (2026, August 30). Slideshow not available after update - Microsoft Q&A. microsoft learn qna Issue: unspecified windows issue in Windows workflow Workflow: Windows workflow
- Microsoft Learn Q&A. (2026, September 1). URGENT: KB5120998 (26200.9278) is wiping all Edge cookie settings on close - Microsoft Q&A. microsoft learn qna Issue: update/install failure in windows update Workflow: windows update
- Microsoft Learn Q&A. (2026, September 1). File History UI and Previous Versions Broken After Installing Recent Windows Updates (KB5101684 / KB5120249) - Microsoft Q&A. microsoft learn qna Issue: update/install failure in windows update Workflow: windows update
- Microsoft Tech Community. (2026, August 30). Title: Severe Font Rendering Issue After Installing KB5122385 and KB5120998 on Windows 11 25H2. microsoft tech community Issue: update/install failure in windows update Workflow: windows update
- Microsoft Tech Community. (2026, August 27). KB5101650 / KB5121003: Thunderbolt 4 NVMe causes WHEA PCIe errors, bugcheck or hang, rollback fixes. microsoft tech community Issue: bsod / stop error in system stability Workflow: system stability
- Microsoft Learn Q&A. (2026, September 6). Windows Store/UWP apps hang in background (no GUI), Wi-Fi forgets profiles, and search indexing broken after KB5120998 update attempt - Microsoft Q&A. microsoft learn qna Issue: update/install failure in windows update Workflow: windows update
- Microsoft Learn Q&A. (2026, September 10). File Explorer reverts to legacy Windows 10 ribbon after KB5120998 (build 26200.9278) — 766 corrupt OOBE payloads in component store; RestoreHealth fails with 0x800f0915 - Microsoft Q&A. microsoft learn qna Issue: update/install failure in windows update Workflow: windows update
Official sources
- Microsoft. (2026, August 27). Windows 11 release information.release health
- Microsoft. (2026, August 27). Windows release health.release health
- Microsoft. Download page.download