Windows update intelligence
KB5124008
September security update · 2026-09-08
Curated snapshot · 2026-10-25. This small collection is not a complete risk assessment. No matching report does not mean an update is safe. Automatic monitoring is not connected.
Update identity
- Windows versions
- 24H2 / 25H2
- OS builds
- 26100.9445 / 26200.9445
- Release type
- Security
- Released
- 2026-09-08
- Last checked
- 2026-10-25
Issues & evidence
3 resultsRemote Desktop Services may become unresponsive
Some environments experienced failed RDP connections or unresponsive management tools after the September 2026 security update.
Plan9 host folders unavailable in Linux VMs
Host folders may be inaccessible in HCS-managed Linux VMs using Plan9.
Domain-joined devices may lose their secure trust relationship
Some Credential Guard protected machine accounts lost their secure channel with on-premises AD domains, blocking interactive sign-in with valid credentials.
Resolution links
Teams and Outlook launch failures on ARM
From KB5121003 · stated scope only
Custom mouse pointers revert unexpectedly
From KB5120998 · stated scope only
Desktop background resets to a solid color
From KB5120998 · stated scope only
An update that supersedes another update does not automatically resolve every associated issue.