Welcome to another monthly review of all the Windows Insider builds which were released in development channels (Dev, Beta, and Release Preview) for testing. This month we are looking back at the cycle of updates released during March 2021.

One thing of note that did happen last month is that Beta and Release Preview channels have not separated into different build branches. The change is indicated by the main build number differences between each channel but the .xxx build numbers continue to be aligned. This means those branches are getting the same updates, just within their own branch.

Here is the rundown on #WindowsInsider builds for March 2021:


It looks like the Dev Channel had a remarkably busy month, but it is misleading. All the .1010 releases, which were pushed out a few days after the previous main build release, were servicing pipeline updates with no new features. At the core, four main builds were released in the Dev Channel in March 2021 including the last one of March that featured all the new icons in the Windows 10 File Explorer.

Beyond the new File Explorer icons, there were other new features shipped out in the Dev Channel during last month:

  • News and Interests taskbar app received a UI refresh with brighter colors.
  • System icons now line up with the Microsoft Fluent Design style.
  • Paste as plain text in clipboard history (WINDOWS KEY + V).
  • 3D Viewer and 3D Paint no longer pre-installed but availagble in the Windows Store for download and installation.
  • Math Input Panel removed due to low usage numbers.
  • Reorder your Windows 10 Virtual Desktops by clicking and dragging them in Task View. Custom desktop backgrounds can now be selected for each desktop to further help differentiate between them. Note: I wrote about the future of Windows 10 Virtual Desktops last month including some critical feature needs to truly make them useful for users.
  • Auto HDR Preview for PC to enhance HDR capable PC’s for gaming visuals.
  • File Explorer Layout updated to padd some space in between various UI elements. A more dense layout remains availabel for those who like to see more information in their UI.
  • Caption Settings updates under Ease of Access.
  • Notepad is now updated via the Windows Store and not with the operating system updates.
  • Windows Terminal and Power Automate Desktop are now included as inbox apps.
  • New File Explorer Icons
  • Improvements to Windows Sandbox and Microsoft Defender Application Guard (MDAG).

In addition to all these noted changes, there is a long list of fixes and enhancements listed for each of these builds.

As you can see, lots of new work in the Dev Channel for Windows Insiders.


As mentioned earlier, the Beta and Release Preview channels have diverged from each other. Beta has now been officially designated as Windows 10 (Version 21H1) and is already recommended for enterprise testing.

Two of the above builds match .xxx build strings with Release Preview Channel because they are the monthly cycle of cumulative updates that helps keep both branches up to date. The other builds in Beta contain specific fixes related to 21H1 to keep it aligned for its upcoming release in the next couple of months.


Release Preview is shipping the preview for monthly cumulative updates for testing before they are released to production installations of Windows 10 (Version 20H1).

What’s Next?

On the feature update release cycle, next up is Windows 10 (21H1) which is being tested in the Beta Channel. As mentioned in previous months, this is a small update in the spring compared to the typical full build feature update that usually arrives in the first half of the year.

From all indications, that big release is going to be this fall. We should have a clearer indication on this in the next couple of months.

Happy Testing #WindowsInsiders!

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