Microsoft has pushed a Windows 11 preview update that adds Shared Audio and NPU tracking, but the same release also flags an install failure tied to cramped EFI boot partitions on older OEM PCs.
The KB5089573 non-security preview landed on May 26, 2026, moving Windows 11 24H2 to OS build 26100.8524 and Windows 11 25H2 to OS build 26200.8524, according to Notebookcheck. The update arrives ahead of June’s Patch Tuesday with consumer-facing features, admin-relevant telemetry, and a known issue connected to May’s mandatory security update.
Microsoft KB5089573 preview brings Shared Audio and NPU tracking to Windows 11
The headline feature is Shared Audio, a new Windows 11 option that sends one audio stream to multiple Bluetooth LE Audio devices at the same time. Microsoft’s flow is direct: open Quick Settings from the taskbar, select Shared Audio, choose two supported paired devices, then select Start Sharing.
That means Windows can now route the same output to combinations cited in the source material, including two pairs of wireless headphones, a speaker and a headset, or a laptop and a soundbar, without manual device switching or third-party software.
The other notable addition is NPU visibility in Task Manager. Windows 11 now surfaces Neural Processing Unit usage as a tracked resource alongside CPU, GPU, and RAM, giving users and administrators a clearer view into when supported on-device AI silicon is active.
KB5089573 also changes Windows Hello behavior. If a user falls back to PIN after face or fingerprint sign-in fails, Windows will restore face or fingerprint as the default method at the next login instead of leaving PIN selected.
A separate accessibility update improves Magnifier in three ways:
- Announcements: clearer screen reader messages when zooming or switching views.
- Protected content: support for magnifying permitted protected content.
- Lens mode: smoother behavior when using the lens view.
Analysis: this is not just a cosmetic preview. Microsoft is pairing visible convenience features with deeper system instrumentation, especially around NPUs. That matters most on newer Windows 11 hardware where AI workloads may shift between CPU, GPU, and dedicated silicon.
Shared Audio targets device juggling as NPU metrics expose AI workloads
Shared Audio addresses a basic Windows friction point: one PC, more than one listening device. The update does not claim universal support across all Bluetooth hardware. It specifically depends on supported paired Bluetooth LE Audio devices.
| KB5089573 feature | What changes in Windows 11 | Practical limit from the source |
|---|---|---|
| Shared Audio | One stream can broadcast to multiple Bluetooth LE Audio devices | Requires supported paired devices |
| Multi-app camera support | Two apps can access the same camera input at once | Applies to the same camera input |
| NPU tracking | Task Manager shows Neural Processing Unit usage | Relevant only where NPU hardware exists |
| Windows Hello default reset | Face or fingerprint returns as default after PIN fallback | Applies after biometric fallback |
| Magnifier updates | Better announcements, protected-content support, smoother lens mode | Feature-specific accessibility changes |
The camera change may be just as useful for some users. Multi-app camera support allows two applications to access the same camera input simultaneously, fixing a conflict the source ties to setups such as Teams or Zoom running alongside OBS or another video app.
NPU tracking gives Windows 11 a more transparent readout for AI PC hardware. Task Manager has long been the place users check whether CPU, GPU, memory, or storage is under pressure; KB5089573 adds dedicated AI silicon to that same operational view.
Microsoft is also continuing Secure Boot certificate renewal in the background, with the June 26 expiration deadline still on track. That makes the update relevant beyond audio and AI telemetry, especially for organizations already watching certificate rollover risk; MLXIO previously covered how the Secure Boot deadline could strand older Windows PCs.
EFI partition install failure hits some older OEM Windows 11 devices
The risk in KB5089573 is not the preview’s new feature set. It is the known issue Microsoft surfaces from KB5089549, May’s mandatory security update.
Some systems fail to complete that installation with error code 0x800f0922 when the EFI System Partition, or ESP, has very little free space. Microsoft calls out devices with 10 MB or less available on the ESP as the danger zone.
Notebookcheck says that range can cover older OEM hardware from 2012 through roughly 2020. The practical failure is an update install problem, not a source-confirmed claim that Windows becomes unbootable.
The ESP matters because it is part of the machine’s boot structure and is touched during servicing. When it is too tight, the Windows servicing layer may not have enough working room to complete the update.
Microsoft’s mitigation splits by device management model:
- Consumer and unmanaged business devices: receive mitigation automatically through Known Issue Rollback.
- Enterprise-managed devices: need a matching Group Policy deployed and a restart for the KIR to apply.
- Confirmed affected machines: can use Microsoft’s registry workaround targeting Boot File Servicing.
Microsoft’s published command is:
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Bfsvc" /v EspPaddingPercent /t REG_DWORD /d 0 /f
That command sets the ESP padding percentage to zero, removing the space buffer the servicing layer demands during installation. The source is explicit that this should be applied only to confirmed affected machines, not used as a routine fleet-wide step.
Windows 11 users should weigh KB5089573 features against preview-update risk
For individual Windows 11 users, KB5089573 is most attractive if Shared Audio, multi-app camera access, or NPU visibility solves a current problem. For everyone else, the stronger reason to pay attention is the ESP issue tied to KB5089549.
For administrators, the prescription is narrower: verify ESP free space on older OEM hardware before pushing May’s security update broadly, especially where devices may fall into the 2012 through roughly 2020 window cited by Notebookcheck. If failures have already appeared, use KIR or the registry workaround only where the symptoms match Microsoft’s known issue.
This update also lands during a busy Windows 11 week. Microsoft is separately testing a revamped docked Copilot sidebar, a design reversal MLXIO covered in Sidebar U-Turn Drags Windows 11 Copilot Back Again.
The next signals to watch are concrete: whether Microsoft changes the KB5089549 known-issue guidance, whether more OEM-era machines surface with 0x800f0922, and how reliably Shared Audio works across supported Bluetooth LE Audio devices. KB5089573 gives Windows 11 useful new controls, but the partition warning is the part that could decide how cautiously IT teams move.
Key Takeaways
- Shared Audio lets Windows 11 users stream one audio source to multiple supported Bluetooth LE Audio devices.
- Task Manager NPU tracking gives users and admins more visibility into on-device AI hardware usage.
- The update also highlights an install failure risk tied to cramped EFI boot partitions on some older OEM PCs.
