Today, Microsoft released Windows 10 Insider Preview build 20251 to the Dev channel. Unsurprisingly, there's nothing new in the build. It's not surprising because with last week's build, Microsoft moved the Dev channel from the rs_prerelease branch to the fe_release branch, and like all 'release' branches, there aren't any new features that arrive.

The 'release' branches used to be reserved for updates that are about to ship. It meant that a feature update was feature-complete, and we were ready for the final phase of testing. Not anymore. Now, Microsoft sort of preps for a fake feature update, just going through the development motions that it's used to. 21H1, if it ships at all, will not ship in this form. If anything, it will be an enablement package like 20H2 was.

It's the exact opposite of what Insiders have signed up for in the Dev channel. After all, when Microsoft overhauled the Windows Insider Program in June, it promised that the Dev channel would be in a perpetual state of rs_prerelease. In fact, that was the precise reason that it was renamed from the Fast ring, because the new name would be more descriptive of what kind of builds you'd get, rather than of how often those builds would arrive.

As for when we'll go back to rs_prerelease and start seeing new features again, I'm hearing the second half of this month. Microsoft has already promised to deliver x64 emulation for Windows on ARM PCs.

While there are no new features, there are a bunch of fixes and known issues. Here's what got fixed:

  • We fixed an issue resulting in the background of some dialogs to unexpectedly appear grey instead of white in the last couple flights.
  • We fixed an issue resulting in the taskbar occluding the Power button in the Start menu for some Insiders recently.
  • We fixed an issue resulting in some Insiders seeing a SYSTEM THREAD EXCEPTION NOT HANDLED bug check.
  • We fixed a crash with opengl32.dll.
  • We fixed an issue that could result in the Settings app hanging when checking for updates right after upgrade.
  • We fixed an issue that could result in the Settings app sending a notification that just said “new notification”.
  • We fixed an issue resulting in the Search Indexer not being able to retrieve metadata from HEIF and WebP files, so you couldn’t search for those files using metadata like date taken.
  • We fixed an issue resulting in the Cast to Device option in Movies & TV (and other media playback apps) not taking any action when clicking on a listed device in recent builds.
  • We fixed an issue in recent builds that could result in the screen you were projecting with Miracast freezing shortly after connecting.

Here's what's still broken:

  • We’re working on a fix for an issue starting with Build 20236 where installing games from the Store to a secondary non-OS drive will result in the secondary drive becoming inaccessible. To prevent this from occurring you must change the default storage for new content to the secondary drive PRIOR to installing the game. This can be done in Settings > Storage > Change where new content is saved.
  • We’re looking into reports of the update process hanging for extended periods of time when attempting to install a new build.
  • Live previews for pinned sites aren’t enabled for all Insiders yet, so you may see a grey window when hovering over the thumbnail in the taskbar. We’re continuing to work on polishing this experience.
  • We’re working on enabling the new taskbar experience for existing pinned sites. In the meantime, you can unpin the site from the taskbar, remove it from the edge://apps page, and then re-pin the site.
  • We’re working on a fix for an issue causing some devices to experience a DPC_WATCHDOG_VIOLATION bugcheck.
  • Windows Insiders on ARM PCs such as the Surface Pro X will notice that Windows PowerShell will fail to launch on this build. As a workaround, please use “Windows PowerShell (x86)” or “Windows PowerShell ISE (x86)” from the Start menu if you need to use PowerShell. Or download the new and modern PowerShell 7 which takes advantage of ARM by running natively. Plus the icon is prettier.
  • We’re investigating reports that some users are seeing error 0x80070426 when using their Microsoft account to sign into various apps. If you encounter it, rebooting your PC may resolve this.

As usual, you can grab today's build from Windows Update. If you're not on the Dev channel yet, you can enroll via the Windows Insider Program tab in Settings.