Windows 10 build 21390.1

Not to be confused with an internal Windows 11 shell build, which bears a similar branch name and an identical build number.
10.0.21390.1.co_release.210521-1658
Build of Cobalt
Screenshot
OS familyWindows 11 (NT 10.0)
Version number10.0
Build number21390
Build revision1
Architecturex86, x64, ARM64
Build labco_release
Compiled on2021-05-21
Expiration date
Timebomb2021-10-31 (+163 days)
SKUs
Home (China, N, Single Language)
Cloud (N)
Pro (China Only, N, Single Language)
Pro Education (N)
Pro (N) for Workstations
Education (N)
Enterprise (N, (N) Evaluation, G (N))
Enterprise multi-session
IoT Enterprise
Team
About dialog
21390 winver.png
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 and to have the Windows 10 User Experience before the new Windows 11 user experience work would be merged. 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.

Updates[a][edit | edit source]

  • 21390.1000.co_release_svc_prod1.210524-1655 (KB5004071)
    • Released on 7 June 2021 to the Dev Channel (x86, x64 and ARM64).
  • 21390.1010.co_release_svc_prod2.210524-1306 (KB5004092)
    • Released on 10 June 2021 to the Dev Channel (x86, x64 and ARM64).
  • 21390.2025.co_release_svc_im.210527-1818 (KB5004123)
    • Released on 14 June 2021 to the Dev Channel (x86, x64 and ARM64).

Gallery[edit | edit source]

Notes[edit | edit source]

  1. According to Microsoft, these builds are in a series of updates in order to test the process of releasing multiple cumulative updates on top of each other. However, several enthusiasts pointed out that Microsoft is releasing cumulative updates because the developers were at the time currently working on merging the Sun Valley work in preparation for the Microsoft event on 24 June 2021.[1][2]

References[edit | edit source]

External links[edit | edit source]