Microsoft: September updates break File History backup feature

Microsoft has confirmed that the April 2026 security updates are causing failures in third-party backup applications using the psmounterex.sys driver. [...]

Microsoft has confirmed that desktop settings are lost or reset on some Windows devices after installing the KB5120998 August 2026 preview update. [...]

Microsoft has fixed a known issue that causes copy-and-paste failures for some Excel users after installing the September 2026 KB5002914 security update. [...]

Microsoft has resolved a known issue that caused Always On VPN connection issues after installing the September 2026 Windows 11 security updates. [...]

The April 2026 KB5083769 security update breaks third-party backup applications from multiple vendors on systems running Windows 11 24H2 and 25H2. [...]