Microsoft has released cumulative update KB5089555 (Build 26220.8491) for Windows 11, version 25H2 for Insiders on the Beta Channel. This build includes a small number of minor bug fixes and improvements aimed at increasing stability, as well as a new voice isolation feature for voice access.
- Voice isolation in Voice Access. A new mode has been added that helps the feature focus on the user's voice even when other people are speaking nearby. In a busy office, an open-plan room, or at home surrounded by family, Voice Isolation filters out extraneous voices and background noise so Voice Access can better recognize speech. All processing happens locally on the device. Three speech recognition modes are now available in Voice Access under Voice Access Settings > Improve speech recognition: Voice Isolation (requires a one-time voice setup), Remove only background noise (filters out non-speech sounds like keystrokes or door slams without extra setup), and No filtering (default microphone input without additional processing). To set up Voice Isolation, select it from the menu and read a short paragraph aloud so Voice Access can learn your voice. This takes about a minute, and voice data never leaves the device.
- Fix for explorer.exe crash loop. A problem has been resolved where after installing the previous build, an explorer.exe crash loop occurred, manifesting as flickering and constant refreshing of the screen or taskbar. After updating, the issue should be fixed.
- Fix for duplicate Energy Saver button. An issue has been fixed where for some Insiders in recent builds, the Energy Saver button in Quick Settings appeared twice.
- Fix for sudden sound cutout. A problem has been resolved where on some devices in recent builds, audio would unexpectedly cut out.
Installation of the update is done through Windows Update: go to Settings > Windows Update and click Check for updates. A computer restart is required to complete the installation.
| Feature / Change | Performance Increase or Decrease | Optimization | PC Speed | Gaming Optimization |
|---|---|---|---|---|
| Voice isolation in Voice Access | ⚪ No direct impact | 🟢 High — Local processing filters background voices/noise; improves recognition accuracy in noisy environments | ⚪ Negligible (processing done on-device with minimal overhead) | ⚪ Not applicable |
| Fix for explorer.exe crash loop | 🟢 High positive — Eliminates UI freezes/flickering; restores stable desktop interaction | 🟢 High — Resolves system process instability; prevents constant taskbar/screen refreshes | 🟢 Noticeably improved — No more resource waste from crash-loop cycling | 🟡 Low indirect — Stable desktop reduces background interruptions during gaming |
| Fix for duplicate Energy Saver button | ⚪ No direct impact | 🟡 Low — UI cleanup; removes redundant button, minor system tray consistency improvement | ⚪ No impact | ⚪ Not applicable |
| Fix for sudden sound cutout | ⚪ No direct impact on compute performance | 🟢 Medium — Restores uninterrupted audio playback, critical for multimedia workflows | ⚪ No impact | 🟢 Medium — Prevents in-game audio loss; avoids immersion-breaking sound drops |
Find and Change Settings
| Setting | Where to find | How to change |
|---|---|---|
| Voice Isolation in Voice Access | Settings > Accessibility > Speech > Voice Access > Improve speech recognition | Open Settings > Accessibility > Speech > Voice Access, then under Improve speech recognition select Voice Isolation. You will be prompted to read a short paragraph aloud for a one-time voice setup. To switch modes, choose Remove only background noise for filtering non-speech sounds or No filtering for default input. |
| Fix for explorer.exe crash loop | N/A (Resolved via Windows Update) | Install the latest update. The explorer.exe crash loop, which caused screen and taskbar flickering, is resolved automatically after updating. No manual configuration is required. |
| Fix for duplicate Energy Saver button | N/A (Resolved via Windows Update) | Install the latest update. The duplicate Energy Saver button in Quick Settings is removed automatically. No manual action is needed. |
| Fix for sudden sound cutout | N/A (Resolved via Windows Update) | Install the latest update. The issue where audio unexpectedly cut out is fixed automatically. No additional settings need to be changed. |
Official announcement on the Microsoft website.
The last 10 Windows updates:
| Update | Build | Version | Windows | Channel | Date |
|---|---|---|---|---|---|
| KB5121157 | 28020.2818 | 26H1 | Windows 11 | Beta | 2026-08-31 |
| KB5121158 | 28120.2824 | 26H1 | Windows 11 | Experimental | 2026-08-31 |
| KB5121794 | 26300.9278 | 26H2 | Windows 11 | Preview | 2026-08-27 |
| KB5121132 | 28120.2760 | 26H1 | Windows 11 | Experimental | 2026-08-21 |
| KB5124040 | 26220.9223 | 25H2 | Windows 11 | Beta | 2026-08-21 |
| KB5124042 | 26340.9233 | 26H2 | Windows 11 | Experimental | 2026-08-21 |
| KB5121106 | 28020.2731 | 26H1 | Windows 11 | Beta | 2026-08-17 |
| KB5121109 | 28120.2738 | 26H1 | Windows 11 | Experimental | 2026-08-17 |
| KB5124036 | 26220.9202 | 25H2 | Windows 11 | Beta | 2026-08-17 |
| KB5124038 | 26340.9212 | 26H2 | Windows 11 | Experimental | 2026-08-17 |