Operating System Beta, etc. Wiki
Windows 10 Iron
Architecture x86, x64, ARM64
SKUs Home
Home China
Home N
Home Single Language
Pro N
Pro Single Language
Pro China Only
Pro Education
Pro Education N
Pro for Workstations
Pro N for Workstations
Education N
Enterprise Evaluation
Enterprise G
Enterprise G N
Enterprise multi-session
Enterprise N
Enterprise N Evaluation
IoT Enterprise
BIOS date 2020-09-04 (Compiled)
Key This build accepts Windows 10 license keys.
Timebomb 2021-01-31 (+149 days)

Windows 10 Build 20211 is the twelfth Insider Preview Build of Iron. It was released to all Insiders in the Dev Channel on 2020-09-10.


  • Made the search box for searching the list of file types, protocols, and apps when choosing a default app in Settings, which was first introduced with Manganese Build 19608 available to all Windows Insiders.
  • You can now attach and mount a physical hard disk from a WSL 2 distro. This feature enables Windows to be able to read the ext file system that is used in Linux. It can be accessed by typing wsl --mount <DiskPath> into PowerShell.


  • Live preview doesn't work for pinned site tabs.
  • The Settings app may crash if you open Manage Disks and Volumes.
  • Some Office applications may either crash or go missing if you update to this build.
  • The Linux kernel is not installed when you use the wsl --install in the Windows Subsystem for Linux. To workaround this issue, run wsl --update to the latest kernel version.
  • Some WSL 2 distros can give you the error "The remote procedure call failed" on startup.
  • Some virtualization software have a chance of giving you a BSOD with the error code KMODE_EXCEPTION.
  • The vEthernet adapter in WSL2 distros can randomly disconnect itself.
  • You may see generic errors when you install WSL through wsl --install.