Windows 10 build 21387 (co_release)
|Build of Cobalt|
|Architecture||x86, x64, ARM64|
|Timebomb||2021-10-31 (+166 days)|
Home Single Language
Pro Single Language
Pro China Only
Pro Education N
Pro for Workstations
Pro N for Workstations
Enterprise G N
Enterprise N Evaluation
Windows 10 build 21387 (co_release) is the nineteenth Insider Preview build of Cobalt, the 21H2 development semester of Windows as a service. This build was released on 21 May 2021 to all Windows Insiders on the Dev Channel.
Changes[edit | edit source]
- Internet Explorer 11's functionality has been disabled and attempting to run its executable file (
iexplore.exe) will open Edge instead. It is still possible to run Internet Explorer if
ieframe.dllis replaced with a copy from an older build.
- The "Eco mode" experimental Task Manager feature introduced in build 21364 has been removed.
- The first log-in has been updated to use smaller and Segoe UI Variable text, though the flashing animation is still kept.
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.
Installation[edit | edit source]
- The update process to this build has a chance of hanging for extended periods of time.
- Some devices might fail to upgrade to this build with error code
0xc1900101due to a second issue different from that in build 21382.
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]
- Certain parts of Search, including the File Explorer search box, are not displaying correctly in the dark theme.
- The icons for Microsoft Edge and File Explorer in the taskbar are swapped in clean installations.