Windows 10 Insider build 21390 is out with new Fluent icons and bug fixes

Laurent Giret

Windows 10 Spotlight Lead Cropped

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Microsoft has just released the Windows 10 Insider build 21390 right in the middle of its annual Build developer conference. Unfortunately, this latest flight for Dev Channel Insiders is a pretty minor one, with the most notable change being new Fluent icons for Task Manager and MSI installers, though today’s blog post didn’t include an image.

Microsoft is also reminding Windows Insiders that the just-released Windows Terminal Preview version 1.9 can now be set as your default terminal emulator on Windows. This new preview version of the command-line tool is a pretty big update, and you can learn more about other new features in our previous post.

Today’s build 21390 also brings fixes for news and interests in the taskbar, the Start Menu, Task Manager, and more. You can see the full list of bug fixes and known issues in the build 21390 below:


  • We fixed an issue causing the news and interests text on the taskbar to appear blurry on some resolutions and scaling factors.
  • We fixed an issue resulting in certain punctuation not being displayed correctly when the display language was Chinese.
  • We fixed a svchost.exe crash related to cdp.dll that some Insiders have been experiencing in recent builds.
  • We fixed an issue impacting Start reliability in recent flights.
  • We fixed an issue where when using dark mode, the text in the File Explorer search box would be black on a black background. Please note this only addresses this dark theme issue in File Explorer, we are continuing to investigate a second issue impacting dark theme when using Search in the taskbar.
  • We fixed an issue in recent flights where a folder might not retain keyboard focus after being renamed in File Explorer.
  • We fixed an issue resulting in Task Manager showing the incorrect icon for some processes.
  • We fixed a second issue causing some devices to fail when updating to this build with error code 0xc1900101. If you continue to receive this error code when attempting to update, please file a new feedback item.

Known issues

  • The Windows Camera App currently does not respect the default brightness setting set via the new Camera Settings page.
  • We’re investigating an issue where Search results are unexpectedly no longer following dark theme as of recent flights.
  • [News and interests] We’re investigating an issue where the flyout may occasionally flash in the top left corner of your screen after clicking the button on your taskbar.

If recent flights in the Windows Insider Dev channel have been pretty light on new features, Microsoft CEO Satya Nadella gave us an exciting taste of things to come during its Build 2021 opening speech yesterday. “Soon, we will share one of the most significant updates to Windows of the past decade to unlock greater economic opportunity for developers and creators. I’ve been self-hosting it over the past several months and I’m incredibly excited about the next generation of Windows,” the exec said.

Microsoft is expected to share more about the future of Windows during a dedicated digital event in the coming weeks, and we’re looking forward to seeing the company finally discuss the big “Sun Valley” design update that should debut with Windows 10 version 21H1 later this year.