Microsoftは8月26日(現地時間)、Windows 11 Version 23H2用のプレビューアップデートKB5064080を公開しました。オプション扱いの更新プログラム(プレビュー版)で、多数の不具合が修正されています。Windows Updateの「更新プログラムのチェック」を利用するか、Microsoft Update Catalogからファイルをダウンロードすることで、手動でインストールすることができます。August 26, 2025—KB5064080 (OS Build 22621.5840) PreviewWindows 11 Version 23H2用の更新プログラムKB5064080では、企業向けバックアップ機能「Windows Backup for Organizations」が正式にリリースされます。Windows 11への移行やAI搭載PCの導入時に、業務の継続性と生産性を維持するためのバックアップ・復元ソリューションです。その他、Copilotキーを押しても再起動できない不具合の修正や、ファイルエクスプローラーの表示・パフォーマンスの改善、Unicode文字の表示不具合の修正などが行われています。リリースノートは以下の通りです。ハイライト[Windows Backup for Organizations]New! Windows Backup for Organizations is now generally available! Experience seamless device transitions with enterprise-grade backup and restore. Whether you're refreshing your organization’s devices, upgrading to Windows 11, or deploying AI-powered PCs, this solution helps sustain productivity with minimal disruption, ensuring business continuity and organizational resilience.改良と修正Normal rolloutImportant: Use EKB KB5027397 to update to Windows 11, version 23H2.This non-security update includes quality improvements. The following summary outlines key issues addressed by the KB after you install it. Also, included are available new features. The bold text within the brackets indicates the item or area of the change.[Copilot] Fixed: Improved the Copilot key’s reliability and resolved an issue that prevented users from restarting Copilot after using the key.[Country and Operator Settings Asset (COSA)] Fixed: This update brings profiles up to date for certain mobile operators.[Device management] Fixed: An issue where the removable storage policy didn’t correctly block external devices such as USB flash drives.[Family Safety] Fixed: An issue where the “Ask to Use” approval prompt didn’t appear when blocked apps were opened. With this fix, apps now show the expected approval prompt when Family Safety settings are enabled.[File Explorer]Fixed: File Explorer might unexpectedly only display a single folder (for example, Desktop), rather than the expected content with recent files and more.Fixed: Syncing more SharePoint sites to File Explorer might slow performance when navigating folders or opening the context menu. This can also affect how quickly files launch.[File sharing] Fixed: This update addresses an issue where accessing files on a Server Message Block (SMB) share over Quick UDP Internet Connections (QUIC) might result in unexpected delays.[File system] Fixed: This update addresses an issue in Resilient File System (ReFS) where enabling deduplication and compression simultaneously could occasionally cause the system to stop responding.[Input]Fixed: This update addresses an issue where certain extended Unicode characters—such as rare Chinese symbols—appeared as blank spaces or incorrect symbols in Windows text boxes. The fix ensures these characters display correctly and maintains compliance with GB18030-2022 requirements.Fixed: This update addresses an issue with the Chinese (Simplified) Input Method Editor (IME) where some extended characters appeared as empty boxes.[Narrator] Fixed: This update addresses an issue where Narrator incorrectly read the name of the Enhance Facial Recognition Protection checkbox under the Facial recognition (Windows Hello) setting.[Network connectivity] Fixed: This update addresses an issue where Wi-Fi might not reconnect automatically after a Group Policy update.[Remote Desktop] Fixed: An issue where cameras didn’t appear during remote sessions after being added or removed. Newly connected cameras were not recognized in Remote Desktop Services (RDS) environmentsIf you installed earlier updates, your device downloads and installs only the new updates contained in this package.既知の不具合更新プログラムには既知の不具合は存在しません。更新プログラムはWindows Updateの他、Microsoft Update Catalogを利用してインストールすることができます。