Microsoftは12月1日(現地時間)、Windows 11 Version 25H2/24H2用のプレビューアップデートKB5070311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。
December 1, 2025—KB5070311 (OS Builds 26200.7309 and 26100.7309) Preview
Windows 11 Version 25H2/24H2用の更新プログラムKB5070311では、Copilot+ PC向けのAI関連機能の改良のほか、一般PC向けのWindows 11の機能の改善が行われています。設定アプリの検索機能の改善や、Windows Spotlightの拡張、ファイルエクスプローラーのダークモードの改善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
Copilot+ PCs experiencesThis section highlights updates and improvements unique to Copilot+ PCs, focusing on AI-powered features, performance enhancements, and user experience optimizations.
[Agent in Settings]
New! The search results menu displays more available results, making it easier to quickly find and modify your settings. A scroll bar lets you view all search results.
New! Recommended settings now makes changes faster by showing an inline agent option for recently modified settings.
New! A dialog now appears when settings can’t be adjusted further. It explains why and provides an option to modify the settings as needed.
[Click to Do]
New!1
The Click to Do context menu now has a streamlined design that makes it easier to access frequently used actions such as Copy, Save, Share, and Open. You can quickly find what you need.New!1
Whenever a large image or table appears on your screen, the context menu automatically opens so you can quickly access actions and view results.[Camera]New! You can use Windows Studio Effects, which provides AI-powered camera enhancements, on an additional camera such as a USB webcam or your laptop’s built-in rear camera. To get started, go to Settings > Bluetooth & devices > Cameras, and select your preferred camera from the connected cameras list. Then, open Advanced camera options and turn on Use Windows Studio Effects. After you turn it on, you can adjust Studio Effects from the camera settings page or the quick settings menu in the taskbar.
[File Explorer]
New! The File Explorer Search Box placeholder text has been updated to highlight the enhanced Windows Search experiences.
New! File ExplorerHome on-hover actions for faster file management (previously released in KB5067036) is now available for enterprise customers.
[Windows Search]New! You can now find your AI-categorized photos from the Microsoft Photos app using Windows Search with semantic search.
1
Functionality will vary by device and market.
Windows 11 PC experiencesThis section highlights new features and enhancements for Windows 11 PCs, including AI-powered capabilities, continuous innovation, and performance improvements.
Improvements and fixes
[Advanced Settings] New! You can now turn on Virtual Workspaces in Advanced Settings. Virtual Workspaces allow you to enable or disable virtual environments such as Hyper-V and Windows Sandbox. To access Virtual Workspaces, go to Settings > Systems > Advanced.
[Desktop Spotlight] New! When Windows Spotlight is set as your desktop background (Settings > Personalization > Background), the context menu now includes two options: Learn more about this background and Next desktop background.
[File Explorer]
New! File Explorer now offers a more consistent dark mode experience. Key actions such as copy, move, and delete dialogs have been updated in both default and expanded views. Progress bars and chart views now align with the dark theme to improve readability. Confirmation dialogs for actions like skip, override, and file selection, along with multiple error dialogs, have also been refreshed for a cohesive look.
New! The simplified File Explorer context menu for easier navigation. Common actions like Share, Copy, and Move now appear in a single organized menu. This change removes clutter and makes commands easier to find, whether you use a mouse, keyboard, or assistive technology. This change will initially be available to a small group of devices as we evaluate the best approach.
Fixed: File Explorer might unexpectedly not show thumbnails for video files containing certain EXIF metadata.
Fixed: A toolbar might sometimes appear unexpectedly in File Explorer.
Fixed: When you right-click a file, the app icon next to the Open option might appear generic instead of showing the default app for that file type.
[Gaming]New! The full screen experience (FSE) is now available on more Windows 11 handheld devices after its initial launch on ASUS ROG Ally and ROG Ally X. FSE gives you a console-style interface with theXbox app, making handheld gaming clean and distraction-free. It improves performance by minimizing background tasks, so gameplay stays smooth and responsive. To turn it on, go to Settings > Gaming > Full screen experience, and set Xbox as your home app. You can open FSE from Task View or Game Bar, or configure your handheld to enter full screen experience on startup.
[Input]New! Pens that support haptic feedback—small vibrations that simulate touch—now provide tactile responses when you interact with the Windows interface. For example, you might feel vibrations when hovering over the close button or when snapping and resizing windows.
[Keyboard] New! Keyboard backlight performance has improved on supported HID-compliant keyboards. Compatible keyboards display keys clearly in low-light environments, and the backlight adjusts to help conserve power.
[Mobile Device Settings] New! You can add and manage your mobile devices in Settings under Bluetooth & Devices › Mobile Devices. On this page you can manage features such as using your device as a connected camera or accessing your device’s files in File Explorer.
[OneDrive]New! The new OneDrive icon now appears in Settings > Accounts > Homepage.
[Recovery] New! Quick Machine Recovery (QMR) now runs a one-time scan on PCs with settings quick machine recovery and automatically check for solutions are both turned on. If a fix isn’t available immediately, QMR directs you to the best recovery options to get your PC running again
[Settings]
New! Keyboard settings for "character repeat delay and rate", and "cursor blink rate", have moved from Control Panel to Settings. You can now find "character repeat delay and rate" under Settings > Accessibility > Keyboard, and "cursor blink rate" under Settings > Accessibility > Text cursor.
New! About in Settings now has an updated layout that organizes device details and related options in one place. You can quickly access features such as Storage settings for faster navigation.
Fixed: Settings might become unresponsive when attempting to navigate to the Network & Internet section.
Fixed: The search bar in Settings might become overlapped with the minimum and maximum buttons in the title bar.
[Taskbar & System Tray]
New! Animations for app groups on the taskbar have been updated. When you hover over app groups on the taskbar, you can see the preview transition as you slide between apps.
New! You can now share an open app window with Copilot directly from the taskbar. When you hover over an open app, you’ll see the option to share its window with Copilot—similar to sharing in Microsoft Teams. Hover over the app icon, select Share with Copilot to start a conversation. Copilot Vision will analyze the content you shared and provide insights based on what’s displayed in that app.
Fixed: The Automatically hide the taskbar setting might unexpectedly turn off, after seeing a message saying a toolbar is already hidden on this side of your screen.
Fixed: Voice access doesn't work correctly when attempting to interact with the taskbar (calling out a number might not invoke that item).
Fixed: The taskbar icons might automatically scale to be smaller, although there is enough room left without scaling changes.
[Widgets]
New! You can choose a default dashboard in Widget Board settings. When live weather is showing, the Widget Board opens the first dashboard in your navigation bar instead of the most recently used one, making the experience consistent. To set your default dashboard, open the full-page Widgets Settings by selecting Settings in the navigation bar, then move your preferred dashboard to the top.
New! Dashboard icons in the Widget navigation bar now show numbers that correspond to the number of alerts from that dashboard. Navigation bar badges clear automatically when you leave a dashboard, making it easy to track what’s new.
[Windows Share]
New!
2 Drag tray now supports multi-file sharing, shows more relevant apps, and makes it easy to move files to a chosen folder.New!2
You can now turn drag tray on or off from Settings > System > Nearby sharing.New!
3 You can share OneDrive files through other apps. The options appear under Share using when you select the Copy link. You must be signed into your Microsoft account.[Display and Graphics]
Improved: Performance has been improved when apps query monitors for their full list of supported modes. When this happens it could previously lead to a momentary stutter on very high-resolution monitors. This work should help prevent and reduce stuttering in these scenarios.
Fixed: All-in-one PCs might experience issues with their brightness slider, where it unexpectedly reverts to the original brightness when interacting with it.
Fixed: Recently certain games might display the message Unsupported graphics card detected, although a supported graphics card is used.
[Game Pass] References to Game Pass in Settings are now modified to reflect updated branding and benefits.
[Start menu] Improved: For users with the new Start menu, the Windows Search panel now matches the new Start menu in size. This update aims to create a smoother transition when searching.
[Lock and Sign-in Screens]
Fixed: It might be very slow the first time when signing into a new account.
Fixed: When your lock screen is set to slide show, there might be a memory leak. Memory leaks can lead to performance or reliability issues over time.
[Smart cards] Fixed: You might unexpectedly see STATUS_NOT_SUPPORTED (0xc00000bb) during sign on when using ECC Smart Card Logon Credential.
[Prism] Windows on Arm devices now have emulation support for applications that use AVX and AVX2, as well as related extensions such as BMI, FMA, and F16C.
2
This feature is gradually rolling out, and availability will vary by device and market. Drag tray might not be available to all devices yet. See KB5058499 for more information about the drag tray feature in Windows Share.3Feature availability depends on your device and market. This feature isn’t available in the European Economic Area.
既知の不具合
更新プログラムには以下の2件の既知の不具合が存在します。
File Explorer might flash with a white screen in dark modeSymptoms
After installing KB5070311, you might experience issues when opening File Explorer in dark mode. The window might briefly display a blank white screen before loading files and folders. This can also occur when you:
Navigate to or from Home or Gallery (including launching to Home)
Create a new tab
Turn the Details pane on or off
Select More details while copying files
Workaround
Microsoft is working to resolve this issue and will provide more information when it is available.
Password icon might be missing or invisible in the lock screen sign-in optionsSymptoms
After installing the August 2025 non-security preview update (KB5064081) or later updates, you might notice that the password icon is not visible in the sign-in options on the lock screen. If you hover over the space where the icon should appear, you’ll see that the password button is still available. Select this placeholder to open the password text box and enter your password. After entering your password, you can sign in normally.
Workaround
Microsoft is working to resolve this issue and will provide information when it’s available.
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。
