Windows 10 build 21390.1

Build of Cobalt
OS family
Architecturex86, x64, ARM64
Timebomb2021-10-31 (+163 days)
Works in
21390 winver.png
Home (N, Single Language, China)
Pro (N, Single Language, China)
Pro Education (N)
Pro for Workstations (N)
Education (N)
Enterprise (G, N)
Enterprise Evaluation (N)
Enterprise multi-session
IoT Enterprise
Cloud (N)
TCB.png TCBGallery.png

Windows 10 build 21390.1 is the twentieth Insider Preview build of Cobalt, the 21H2 development semester of Windows as a service, and is the last known build of Windows 10 (excluding CUs) before the announcement of Windows 11. This build was released to the Dev Channel on 26 May 2021.

Changes[edit | edit source]

  • Task Manager and Windows Installer packages now have updated icons.
  • The Mail and Microsoft Store apps are no longer pinned on the taskbar by default on clean installations.

Bugs[edit | edit source]

News and interests[edit | edit source]

The flyout might occasionally flash in the screen's top left corner when opened.

Camera Settings[edit | edit source]

The Camera app does not respect the brightness adjustments made to a camera under its respective page.

OOBE[edit | edit source]

The OOBE may use an incorrect font when this build is ran under Simplified Chinese language pack.

General[edit | edit source]

  • The update process to this build has a chance of hanging for extended periods of time.
  • Search results in the taskbar flyout are not displaying correctly in the dark theme.
  • The icons for Microsoft Edge and File Explorer in the taskbar are swapped in clean installations.
  • In some cases, audio and video devices that are installed on the system may not work despite showing up in device manager. The chances of the user encountering this bug increases the longer they use this build.

Upgrade[edit | edit source]

  • There is a chance that the default app mode color will be reverted back to Light from Dark.
  • Sometimes the build may use an incorrect font in several languages.

Gallery[edit | edit source]

External links[edit | edit source]