Microsoft has released a new Windows 11 preview build 27858 for Windows Insiders in the Canary channel.

Full build number: 10.0.27858.1000.rs_prerelease.250512-1209.

↑ Changes and Improvements

• Input:
  • Microsoft is testing a new way to open the Emoji Panel in Windows 11. Developers have added a new icon to the notification area on the taskbar. This will help you quickly express yourself using emoji, GIFs, kaomoji, etc. across all Windows apps and interfaces. The WIN + . shortcut still works, and its information appears in the new icon's tooltip. You can hide this icon by right-clicking it and going to taskbar settings.
    

↑ Fixes

• General:
  • Fixed an issue causing black screens for some Insiders when updating to the previous build.
  • Fixed missing text in various system parts after the previous build.
• File Explorer:
  • Enhanced text scaling support in File Explorer, Open/Save dialogs, and file copy windows. Configure in Settings > Accessibility > Text size.
• Desktop Icons:
  • Updated logic for desktop app icons. Packaged apps will no longer show accent color backgrounds (e.g., when dragging Snipping Tool icon from Start to desktop). Icons are also larger for better visibility.
• Input:
  • Fixed voice typing not launching from touch keyboard in narrow Simplified Chinese layout.
  • Fixed frequent ctmon.exe crashes affecting text input.
• Windows:
  • Fixed explorer.exe crashes related to snap layouts when dragging windows or hovering over Maximize buttons.
• Taskbar:
  • Fixed taskbar icons not properly enlarging in tablet mode.
  • Fixed incorrect arrow key navigation after WIN + T on Arabic/Hebrew systems.
• Graphics:
  • Fixed Night Light not working for some Insiders in previous builds.
  • Fixed unexpected FPS caps for some Insiders in the previous build.
• Networking:
  • Fixed Wi-Fi connectivity issues for some Insiders.
• Audio:
  • Fixed MIDI devices not being recognized in recent Canary builds.
• Other:
  • Fixed GSOD (KERNEL_SECURITY_CHECK_FAILURE) for some Insiders after updating to the previous build.
  • Fixed GSOD (SYSTEM_THREAD_EXCEPTION_NOT_HANDLED) for some Insiders after updating to the previous build.
  • Fixed inability to set JXR HDR images as desktop backgrounds on ultrawide (21:9) monitors.

↑ Known Issues

• General:
  • [Important note for Copilot+ devices] When switching to Canary channel from Dev, Release Preview or stable Windows on Copilot+ devices, you may encounter PIN/biometrics login issues with error "Something went wrong, your PIN isn't available" (code 0xd0000225). Click "Set up PIN" to recover.
  • [New] Group Policy Editor may show an error about administrative templates. Clicking "OK" allows normal operation.
• Input:
  • [New] Pen input may not work on some devices.

Happy testing!

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