Microsoft has released a new Windows 11 preview build 27863 for Windows Insiders in the Canary channel.

Full build number: 10.0.27863.1000.rs_prerelease.250517-1909.

↑ Changes and Improvements

• Post-Quantum Cryptography:
  • As announced at Build 2025, Microsoft has added support for the ML-DSA post-quantum signature algorithm in NCrypt and BCrypt cryptography APIs, as well as Crypt32 certificate APIs. Three variants are supported: ML-DSA 44, 65, and 87. Microsoft recommends testing ML-DSA certificate usage and validation with these changes.

↑ Fixes

• Windows Sandbox:
  • Fixed an issue preventing Windows Sandbox from launching in previous builds (error code 0xc0370106).
• Other:
  • Resolved an issue where core Windows UI components (File Explorer, Start Menu) wouldn't load in Safe Mode.
  • Fixed an msftedit.dll issue causing crashes in Arabic/Hebrew systems for apps like Sticky Notes and Dxdiag.

↑ Known Issues

• General:
  • [Important for Copilot+ devices] When switching to Canary from Dev/Release Preview/Stable channels, Copilot+ devices may encounter PIN/biometrics login failures with error "Something went wrong, your PIN isn't available" (code 0xd0000225). Use "Set up PIN" to recover.
  • Group Policy Editor may display an administrative templates error message. Clicking "OK" allows normal operation. One fix is included in this build, with another coming soon.
  • Engineers are investigating missing Acrylic effects on the Taskbar after updating.
  • Engineers are investigating audio playback issues for high sample rate (e.g., 192Hz) multi-channel devices after updating.
• Input:
  • Pen input may not work on some devices.
• Task Manager:
  • Search and filtering features aren't functional in this build.

Happy updating!

Source