Windows 11 26H1 build 28000.2340 (KB5095091) — release notes, downloads, known issues

Windows 11 · 26H1 · Release · Optional preview update

Windows 11, version 26H1 (28000.2340)

Release
KB5095091 — Microsoft's article, opens in a new tab
Jun 23, 2026
amd64
arm64

Windows 11 26H1: Ships on new silicon only

Download amd64 — build 28000.2340 from UUP Dump, opens in a new tab Download arm64 — build 28000.2340 from UUP Dump, opens in a new tab All 26H1 builds JSON — this build from the builds API

AI summary

Windows 11 version 26H1 (28000.2340) is a platform-only Canary build focused on stability, shipping security-relevant platform servicing and targeted bug fixes like Live Captions and Outlook credential window issues.

Generated from the package's release notes and forum coverage. Verify against Microsoft's release-health page before acting on it.

Microsoft's known issues — KB5095091

Issue Known issue Microsoft has received reports of an issue in which certain third-party applications might be unable to launch Microsoft Office applications or open documents after installing the Windows updates released on or after June 9, 2026. This issue affects certain third-party applications that use OLE automation to interact with Microsoft Office applications. In some cases, the Office application or document might fail to open without displaying an error message. Affected Microsoft Office applications might include Word, Excel, PowerPoint, Access, and other Microsoft Office applications when launched from within the affected third-party application. Reports indicate that this issue may affect appli Workaround: This issue is resolved in Windows updates released on and after July 14, 2026 such as KB5101649 . We recommend you install the latest Windows update for your device as it contains important improvements and issue resolutions, including this one.

Microsoft's release notes for KB5095091 ›