Microsoft has released cumulative update KB5124137 (Build 26340.9502) for Windows 11 version 26H2 for Insiders in the Experimental channel. Update KB5124137 brings a new mouse indicator animation, a contrast theme in Magnifier, two additions to Cloud Rebuild cloud recovery, and a sound setting for screen readers in Automatic captions. The changes are rolling out to Insiders gradually, so they will not appear for everyone at the same time.
- Mouse indicator. The mouse indicator has a new, smoother animation that is enabled in Settings > Accessibility. An option has been added in which the indicator remains on until the Esc key is pressed.
- Magnifier. Magnifier now has a contrast theme toggle for those who find it uncomfortable to look at a bright screen. Previously, in such a situation, color inversion was enabled, but it changes the entire image, including photos, charts, and videos. The toggle is located directly on the Magnifier toolbar. By default, the dark theme is applied, and you can choose which contrast theme it enables in Settings > Accessibility > Magnifier. The contrast theme recolors only the interface: photos, videos, and charts retain their original colors. Color inversion works as before; the contrast theme is a separate feature, not a replacement.
- Cloud Rebuild. Cloud Rebuild cloud recovery has received two additions. During recovery, you can now clean the computer's drives. When starting recovery in the WinRE environment, two options are available: delete files if the computer remains yours, or delete files with drive cleaning before recycling, returning, or transferring the computer to another person. The second option uses the drive's own cleaning tools, securely erases data before reinstalling Windows, and is irreversible. IT administrators can configure and launch Cloud Rebuild remotely through Recovery CSP, with an already installed build or with a specified target.
- Automatic captions. A setting has appeared that allows screen reader sound to be included in captions. By default, it is turned off, and Automatic captions do not transcribe the speech of Narrator, JAWS, and NVDA, showing only microphone and system sound.
- Hyper-V. Fixed a bug due to which applications with virtual machines managed by the Host Compute Service (HCS) could not work with host shared folders through Plan9: folders opened from a Windows computer did not appear in the Linux guest system or were unavailable.
- Other. Fixed a bug due to which backup in File History unexpectedly ended with a message that no suitable drives were found.
Installing via Windows Update: go to Settings > Windows Update and click Check for updates. A computer restart will be required to complete the installation.
| Feature / Change | Performance Gain / Loss | Optimization | PC Speed | Gaming Optimization | Impact Metrics + Micro Explanation |
|---|---|---|---|---|---|
| Mouse indicator: smoother animation + option to keep indicator until Esc | ⚪ No measurable gain/loss | 🟡 Slight UX optimization | ⚪ No impact | ⚪ No impact | 🟡 ~0% perf change; smoother visuals only, negligible CPU/GPU cost |
| Magnifier: contrast theme toggle (separate from color inversion) | ⚪ No measurable gain/loss | 🟢 Good accessibility optimization | ⚪ No impact | ⚪ No impact | 🟢 ~0–1% overhead; recolors UI only, media stays original colors |
| Cloud Rebuild: drive cleaning during recovery + remote config via Recovery CSP | 🔴 Possible slowdown during recovery (secure erase takes time) | 🟢 Strong admin/IT optimization | 🔴 Temporary slowdown during wipe (expected) | ⚪ No impact | 🔴 Recovery time +10–40% with secure erase; irreversible, uses drive's own tools |
| Automatic captions: option to include screen reader sound (Narrator, JAWS, NVDA) | 🔴 Minor CPU load when enabled | 🟡 Accessibility optimization | ⚪ Negligible impact | ⚪ No impact | 🔴 ~1–3% CPU while active; off by default, transcribes mic + system sound only when enabled |
| Hyper-V: fixed Plan9 shared folders bug with HCS-managed VMs | 🟢 Performance restored for affected setups | 🟢 Critical bug fix | 🟢 Fixes broken host-guest folder access | 🟡 Indirect (VM/dev/gaming-in-VM use) | 🟢 Up to 100% functionality restored; folders now appear in Linux guests |
| Other: fixed File History backup "no suitable drives found" error | 🟢 Backup now completes reliably | 🟢 Reliability fix | ⚪ No speed change | ⚪ No impact | 🟢 Failure rate → ~0%; backup no longer aborts unexpectedly |
Official announcement on the Microsoft website.
The last 10 Windows updates:
| Update | Build | Version | Windows | Channel | Date |
|---|---|---|---|---|---|
| KB5126657 | 19045.7807 | 22H2 (ESU) | Windows 10 | Stable | 2026-10-13 |
| KB5126653 | 22631.7652 | 23H2 | Windows 11 | Stable | 2026-10-13 |
| KB5127646 | 28000.3231 | 26H1 | Windows 11 | Stable | 2026-10-13 |
| KB5127648 | 26300.9711 | 26H2 | Windows 11 | Stable | 2026-10-13 |
| KB5127757 | 28120.3181 | 26H1 | Windows 11 | Experimental | 2026-10-07 |
| KB5127758 | 26220.9606 | 25H2 | Windows 11 | Beta | 2026-10-07 |
| KB5127754 | 28020.3172 | 26H1 | Windows 11 | Beta | 2026-10-07 |
| KB5127753 | 26340.9616 | 26H2 | Windows 11 | Experimental | 2026-10-07 |
| KB5124192 | 28120.3151 | 26H1 | Windows 11 | Experimental | 2026-10-02 |
| KB5124196 | 28020.3142 | 26H1 | Windows 11 | Beta | 2026-10-02 |