KB5089573

Microsoft has released preview update KB5089573 (build 26200.8524) for Windows 11 version 25H2 (2025 Update). The cumulative package is intended for devices based on x64 (amd64) and ARM64 processors.

The update is delivered in two phases — gradual rollout and normal rollout. In gradual rollout, the update is delivered in parts, and features do not reach devices simultaneously — their availability depends on the specific device. Normal rollout is a broad release to all compatible devices at the same time, typically when general availability (GA) is reached.

Below are the improvements and fixes included in KB5089573. Some of them are distributed gradually and may not be available immediately on all devices. The following is a list of new features and updates, followed by known issues and installation instructions.

Updated: 19.05.2026. Microsoft has updated the build numbers and fixed several issues encountered by Release Preview channel insiders after installing the previous build:

• Fixed an issue – on certain devices, sound would unexpectedly turn off;
• Fixed a hang in the Windows Push Notification (WPN) service, which prevented some apps from launching and notifications from working.

Updated: 27.05.2026. Update KB5089573 (Build 26200.8524) Preview for Windows 11, version 25H2 is available for installation in Windows Update as a preview update and for manual download in the Microsoft Update Catalog.

After installing this update (KB5089549), on some devices the installation may not complete with error code 0x800f0922. The issue occurs on devices with low free space in the EFI System Partition (ESP), especially if 10 MB or less is available. On affected devices, the update installs successfully during the initial stages, then the installation is interrupted during the reboot stage at approximately 35–36%, after which Windows rolls back the update with the message Could not complete the setup. Undoing changes, and the installation completes with error code 0x800f0922. In the log C:\Windows\Logs\CBS\CBS.log, entries indicating insufficient free space in the ESP appear: SpaceCheck: Insufficient free space, ServicingBootFiles failed. Error = 0x70 and an entry about space occupied by third-party or OEM files outside Microsoft boot directories.

• Error 0x800f0922 due to lack of space in the ESP partition. On devices with low free space in the EFI System Partition (especially 10 MB or less), the update is interrupted during the reboot stage at approximately 35–36%, after which a rollback occurs with the message Could not complete the setup. Undoing changes and error code 0x800f0922 is logged. The CBS.log records entries about insufficient free space and about files outside Microsoft boot directories.

Affected users can use one of the workarounds. Option 1 — allow the installation by changing the ESP registry parameter: open Command Prompt as administrator, run the command reg add "HKLM\SYSTEM\CurrentControlSet\Control\Bfsvc" /v EspPaddingPercent /t REG_DWORD /d 0 /f, restart the device, and retry the update installation. Incorrectly editing the registry may cause serious issues, so you should back up the registry before making changes. Option 2 — resolution via Known Issue Rollback (KIR). The fix has already been automatically distributed to consumer and unmanaged enterprise devices, and restarting the device will help apply it faster. On devices managed by an IT department, administrators can apply the fix by installing and configuring a special Group Policy under Computer Configuration > Administrative Templates. The policy temporarily disables the change causing the issue; after applying it, devices must be restarted. A full solution is being prepared and will be included in a future Windows update.

• Shared audio listening. New feature allows two users to listen to audio from the same PC simultaneously on Windows 11. The technology uses Bluetooth LE Audio broadcast. Usage scenarios include watching a movie together while traveling or listening to music during joint study sessions. To start streaming, open Quick Settings from the taskbar, select Shared Audio, specify two paired and connected compatible devices, and click Start Streaming.
• Screen magnifier. The screen magnifier now provides clearer and more consistent announcements when working with a screen reader. Voice prompts accompany zooming in and out, switching modes, enabling and disabling color inversion, as well as turning the magnifier itself on and off. Added support for magnifying protected content. Improved smoothness of screen magnifier movement in Lens mode.
• Task Manager. Expanded capabilities for monitoring NPU load on PCs with an NPU. Added optional NPU and NPU Engine columns on the Processes, Users, and Details tabs, as well as NPU Dedicated Memory and NPU Shared Memory columns on the Details tab. Neural engines that are part of the GPU are now displayed on the Performance tab — providing a more complete picture of AI-related activity. A new optional Isolation column on the Processes and Details tabs shows which applications are running in an AppContainer. Any of the new columns can be added via the column header context menu. Fixed CPU frequency display on the Performance tab in virtual machines after exiting hibernation — inflated values no longer appear.
• Camera. New Multi-App Camera feature allows multiple applications to access the camera video stream simultaneously. Basic Camera mode provides simplified camera functionality — useful for troubleshooting or improving stability when the device is malfunctioning. Organization administrators can now set Multi-App Camera or Basic Camera modes via Group Policy under Computer Configuration > Administrative Templates > Windows Components > Camera > Configure camera settings.
• General performance. Faster launch of applications and basic shell elements — Start menu, search, and Notification Center.
• Windows Hello. Optimized WinBio service — reduced latency when exiting Modern Standby. Reduced frequency of unexpected Windows Hello Enhanced Sign-in Security authentication blocks — fixed an issue with missing secure registration metadata.
• Storage. When creating a Dev Drive in the dialog box, you can now specify the size in gigabytes rather than only in megabytes. The same applies to resizing volumes through Settings > System > Storage. Updated Settings > System > Storage section — now the UAC prompt appears not when opening the page, but only when navigating to view temporary files.
• Personalization. Improved accuracy of accent color selection matching the desktop wallpaper when automatic accent color selection is enabled in personalization settings. Improved reliability of wallpaper preservation between reboots and system updates, including enhanced support for high-resolution wallpapers and other scenarios — eliminating fallback to a solid background.
• USB. Improved reliability of displays connected via USB4 docks and hubs. Their image now appears more stably when exiting sleep mode. The USB3 stack received additional resilience and recovery mechanisms for certain hardware failures. USB devices operate more reliably.
• Sensors. Improved protection against applications that might keep the sensor hub powered on and drain battery.
• HID devices. Extended battery life in scenarios where there are malfunctioning HID devices in the system — the operating system no longer keeps the HID/Input stack active for them. Also improved power hygiene regarding applications that might initiate data exchange with HID devices during sleep mode.
• Input. Improved reliability of invoking the touch keyboard on the login screen when entering or changing a password. Improved stability of explorer.exe when closing the input switcher. Faster opening and navigation of the clipboard history.
• Fonts. Improvements to the rendering of combined diacritical marks in Greek and Cyrillic alphabets within the Times New Roman font family. Fixed character positioning issues — text displays more accurately and uniformly, enhancing readability and eliminating rendering inconsistencies.
• Task Scheduler. Task Scheduler now preserves column width settings in the task list view between sessions.
• Desktop icons. Improved reliability of loading application shortcuts on the desktop.
• Microsoft Store. Changes made to improve download performance and optimize bandwidth usage. Improved error reporting when downloads fail due to enabled Windows Update Group Policy.
• Reliability. Improved Windows reliability on login and lock screens, in File Explorer, when using gestures on touch devices, and when changing themes in Settings.

As part of normal rollout, this non-security update includes quality improvements. Key change: additional high-confidence targeting data for Secure Boot has now been added to Windows quality updates — this expands the scope of devices that automatically receive new Secure Boot certificates. Certificates are delivered only after receiving sufficient successful installation signals, ensuring controlled gradual rollout.

If you have installed previous updates, only the new updates contained in this package will be downloaded and installed. To install KB5089573, go to Settings > Windows Update and click Check for updates. A system restart is required to complete installation. After the update, the Windows 11 build number will change to 26200.8524.

How the new features work:

Shared audio listening: The feature implements simultaneous transmission of an audio stream from a single PC to two Bluetooth devices via the Bluetooth LE Audio stack using Connected Isochronous Stream (CIS) isochronous channels. The system mixer routes a unified audio session to the A2DP/LE Audio profile, where an audio codec (e.g., LC3) encodes the stream, and the Bluetooth controller multiplexes it into two independent logical transport channels to synchronized receivers, minimizing desynchronization. Activation is performed via Quick Settings, initiating a broadcast session through Windows.Devices.Bluetooth.Background.

Screen magnifier: The screen magnifier mechanism has been extended with integration into the UI Automation API to generate voiced LiveRegionChanged events when zooming, switching modes, or inverting colors. In Lens mode, frame interpolation has been improved: motion smoothing is achieved through an increased cursor position polling rate and double buffering of the resulting screen buffer fragment. Protected content rendering now leverages the protected overlay mechanism (protected media path), allowing secure frame capture from the DRM sandbox without breaking the trust chain.

Task Manager: NPU monitoring has been added via the WMI provider Win32_PerfRawData and NpuTraceSession, which reads neural engine utilization metrics as a percentage, as well as dedicated (DedicatedMemory) and shared (SharedMemory) memory. The Performance tab now displays GPU neural blocks by polling KMD (Kernel-Mode Driver) counters via DxgKrnl. The Isolation column identifies processes in application containers by checking the IsAppContainer flag in EPROCESS->Win32Process. An issue with inflated CPU frequency in VMs after hibernation has been fixed: Task Manager now resets cached % Processor Time values upon detecting an S4 exit event.

Camera: Multi-App Camera uses a system proxy driver DevProxy that multiplexes the video stream from a physical device into multiple virtual channels. Each client process receives an isolated IMFCaptureSource instance, while the proxy layer performs frame buffer copying in userspace to avoid race conditions. Basic Camera mode forcibly restricts the capture pipeline to basic Media Foundation transforms, disabling advanced processing such as HDR, stabilization, or background blur. Mode management via Group Policy sets the registry key HKLM\Software\Policies\Microsoft\Windows\Camera, configuring MultiAppAccess and BasicMode.

General performance: Faster launch is achieved through pre-compilation of XAML markup into native structures via XamlDirect and aggressive caching of ready-made UI trees in Standby List memory. For Search, indexer initialization time has been reduced by deferred loading of ISearchCatalogManager providers. The Notification Center uses a background thread rendering technique with subsequent DirectComposition compositing, reducing first-frame latency.

Windows Hello: WinBio service optimization aims to reduce latency when resuming from Modern Standby: the biometric stack now caches the Secure Device Connector (SDC) session, avoiding a full TPM authentication cycle upon resume. For Enhanced Sign-in Security, a bug involving missing SECURE_REGISTRATION_METADATA in the NGC store, which caused unscheduled blocks, has been fixed. Validation now occurs through key synchronization with Azure AD.

Storage: In the Dev Drive creation dialog and Storage Settings page, the size field now accepts values in gigabytes, automatically converting them to megabytes with rounding to ReFS cluster boundaries (64K). Volume parameters are modified through IVdsVolume. The UAC prompt for the "Temporary files" section is now deferred: instead of elevating privileges upon page opening, an administrator token is requested only when attempting to access the protected Win32_VolumeCache branch via Shell::Execute with the runas verb.

Personalization: The automatic accent color selection algorithm analyzes wallpapers using a k-means clustering method in the LAB color space, isolating dominant and complementary shades with improved accuracy thanks to noise filtering and color contrast consideration. The wallpaper preservation mechanism has been modernized: instead of writing a path to the registry (WallPaper key), the system creates a cached copy of both resolutions in %AppData%\Microsoft\Windows\Themes\CachedFiles, preventing fallback to a solid color when the source file is unavailable during a reboot.

USB: USB4 display stability has been enhanced by implementing DisplayPort Alt Mode initialization retries via DP packet tunneling in the USB4 router. When resuming from sleep, the UcmCx driver now waits for full USB4 link recovery before sending a hot-plug event to the graphics subsystem. The USB3 stack received additional failure handlers: for transaction errors, a multi-level recovery mechanism is implemented — from transparent TD retry to endpoint reset via ClearFeature.

Sensors: The sensor power management system now more aggressively transitions the Sensor Hub to D3 (off) by monitoring, through DevicePowerStates, the activity of applications holding a wake-lock via ISensor interfaces. A timeout heuristic is introduced: if an application does not request new reports within a set period while the screen is locked, the sensor API forcibly powers down the hub, ignoring the client's ref-count.

HID devices: For malfunctioning HID devices that cyclically trigger interrupts, a suppression mechanism has been introduced: the HidClass driver monitors the error frequency and, upon exceeding a threshold, places the device into a "quiet" mode, resetting the PDO stack without continuous retries to read descriptors. A sleep-mode power filter has been implemented: the InputSuppression component blocks application attempts to exchange data with HID devices when the system transitions to S3/S0ix.

Input: Invocation of the touch keyboard on the login screen is forced via the ITextInputPanel API with a CredUI context check, ensuring reliable appearance even during a cold session start. Explorer.exe stability has been improved by fixing a race condition in the input switcher: calling Deactivate() on a closed language bar host window no longer leads to a double resource release. Clipboard history has been accelerated by caching recent items in the ClipboardServer process memory with asynchronous loading of the rest.

Fonts: In the Times New Roman font, the logic for forming combined diacritical marks has been corrected: mark anchor positioning in GPOS tables has been adjusted, enabling correct positioning of superscript and subscript diacritics for Cyrillic (e.g., Ӝ, Ҿ) and Greek characters. Rendering now performs glyph composition via Uniscribe/DirectWrite with correct offset calculated based on the updated vectors in the GDEF table.

Task Scheduler: Task Scheduler now saves column widths in the list view, serializing ListViewColumnWidths states into a binary registry block at the path HKCU\Software\Microsoft\Windows NT\CurrentVersion\Schedule\View. Upon loading the MMC snap-in, the console reads the values, restoring user preferences.

Desktop icons: The reliability of desktop shortcut loading has been increased by introducing asynchronous integrity verification of .lnk files via IShellLink with retries for target path resolution. If the target executable is temporarily unavailable at shell startup, instead of removing the shortcut, the system places it in a queue for deferred Shell cache refresh.

Microsoft Store: The download mechanism has been optimized by switching to parallel chunking with an adaptive block size, dynamically adjusted based on channel bandwidth measured through BackgroundTransfer. Error diagnostics have been improved: when downloads are blocked by Group Policy DisableOSUpgrade or TurnOffStore, the Store now translates the exact error code 0x80070422 with a failure reason message in the UI.

Reliability: Fault tolerance in sign-in scenarios has been increased through refactoring of LogonUI initialization: critical authentication components have been isolated into a separate host process, the crash of which does not destroy the session. In File Explorer, COM object handle leaks occurring during frequent navigation have been eliminated. Touchscreen gesture processing has been stabilized by correcting timestamps in the WM_TOUCH/WM_GESTURE chain. Theme changes systemically dampen the broadcast change notification queue, eliminating race conditions when updating all UI elements.

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