There is no data from the Microsoft Security Update Guide for KB5124010 – for example for an optional preview update or an update from another vendor. Affected according to our entries: Microsoft Windows 11 24H2/25H2, Microsoft Windows 11 File History, Microsoft Windows 11 23H2, 24H2, 25H2, 26H1 and Windows 10 ESU, Microsoft Windows 11, Version 26H2. Known issues with this update: 2 open, 1 with workaround, 4 fixed.
Users report various problems after installing the KB5124010 preview update for Windows 11 24H2/25H2: slow boot, shutdown and search, a boot failure after uninstalling, and games crashing. These are reported by users, not yet confirmed by the vendor. Only 2 independent sources were found. A separate AC-3 (Dolby Digital) app crash is mentioned as resolved by KB5127648 according to the research notes.
Users report that File History copies files to the target drive, but the "Last copied on" date does not update and Previous Versions shows no entries. This is reported by users, not yet confirmed by the vendor. A related September 2026 File History bug was reportedly resolved by Microsoft, but no vendor source confirms the remaining problem.
File History is reported to show a false 'Reconnect your drive' message after the 8 Sep 2026 update, and backups stop working. This is reported by users, not yet confirmed by the vendor. A fix is reported to be available with KB5124010, but one report says part of the problem persists.
Microsoft · Windows 11 23H2, 24H2, 25H2, 26H1 and Windows 10 ESU
After installing Windows 11 version 26H2, Credential Guard protected machine accounts may lose their secure channel to an on-premises Active Directory domain. The cause is Machine Identity Isolation (MII), which Windows now honours; it is only supported with Windows Server 2025 domain controllers at Domain Functional Level 2025 or above. Microsoft has resolved the issue with updates released on 2026-09-22 and later.
After the Windows updates of September 22, 2026 (KB5124010) and later, some applications that need to decode AC-3 (Dolby Digital) audio might close unexpectedly. Microsoft has resolved the issue with the updates released October 13, 2026 (KB5127648) and later.
After the September 2026 preview update, non-admin users might be unable to connect via Remote Desktop to devices that have Administrator protection enabled. Microsoft resolved the issue with updates released on 2026-10-28. For Windows 11 24H2 the release health page still shows the issue as mitigated, with a fix planned for a future update.
After installing Windows 11, version 26H2 and subsequent updates, some devices may fail to load the desktop after sign-in. The issue was mainly observed on Azure Virtual Desktop (AVD) hosts using FSLogix, more often with some existing user profiles. Microsoft resolved it with the updates released on 2026-10-13 (KB5127648) and later.
We continuously read the vendors’ official sources, community reports and trade media and summarise them in our own words, with a link to the source:
Microsoft: Windows release health (Windows 10/11, Server 2016 to 2025), Windows message center, known issues of Microsoft 365 Apps (Outlook, Excel, Word, PowerPoint), Edge, Intune, Autopilot, Windows 365 and Entra Connect, Microsoft KB articles with timelines, Exchange and Windows IT Pro blogs, optionally Microsoft 365 service health and message center
other vendors: Veeam KB, Citrix (known issues), Ubuntu and Debian (regressions), Broadcom (VMware), Fortinet, Cisco, Mozilla, Let’s Encrypt
community (title, short excerpt and link only, without the names of the authors): Microsoft Q&A, Microsoft Tech Community (discussions), Veeam R&D Forums, Eleven Forum
targeted web research with AI (Claude), e.g. on the updates of the month – this also finds discussions on Reddit and in forums; such entries are labelled as community reports until the vendor confirms them
early warning from trade media (title and link only): Born’s Tech and Windows World, BleepingComputer, AskWoody, Windows Latest, Windows Central, gHacks, The Windows Club, Deskmodder, Dr. Windows, WindowsArea, Frankys Web, heise online
Summary and translation with AI (Claude by Anthropic) – without any data of visitors.
Affected? We can help.
We check whether your systems are affected, apply workarounds properly and plan for dated changes in good time.
