Windows Insiders on the Dev channel can now test x64 app emulation on windows 10 on ARM PCs

Microsoft has just announced some big news for Windows Insiders in the Dev channel. The software giant started releasing build from a new FE_RELEASE development channel a couple of weeks ago, and the Windows Insider has just announced a new branch split with two new separate builds coming from the FE_RELEASE and the RE-PRELEASE branches.

Starting today Windows Insiders in the Dev Channel who were previously receiving builds from the FE_RELEASE branch can opt in to install the RS_PRERELEASE build 21277, which brings support for x64 emulation on Windows 10 on ARM PCs. Microsoft will continue to release builds coming from the FE_RELEASE branch in the coming weeks, and the new build 20277 is available today for Dev Channel Insiders who do not choose to install the RS_PRERELEASE build 21277 in Windows Update;

“Insiders who choose to stay put will continue to automatically get builds from the FE_RELEASE until we move all Insiders in the Dev Channel to receiving RS_PRERELEASE builds sometime after the holidays. We still need Insiders running FE_RELEASE builds and giving us feedback on these builds so its ok if you choose to stay on these builds,” the Windows Insider team explained.

Keep in mind that it won’t be possible to install FE_RELEASE builds once you choose to install a RS_PRERELEASE build on your PC. These separate branches will also have a different set of fixes and known issues, and here’s the list for the Build 20277 (FE_RELEASE) below:

Fixes

• We fixed an issue that could result in the WinRE volume label being lost after multiple upgrades.
• We fixed an issue that could result in apps failing to update with error code 0x80073D02.

Known issues

• 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 resulting in some users seeing error 0x80070426 when using their Microsoft account to sign into various apps. If you encounter it, rebooting your PC may resolve this.
• We’re working on a fix for an issue where, in recent Dev Channel builds, no drives appear under Settings > System > Storage > Manage Disks and Volumes. As a workaround, you can manage your disks in the classic Disk Management tool.

Microsoft did also provide a list of changes, fixes and known issues for the build 21277 (RS_PRERELEASE), but the introduction of x64 emulation on Windows 10 on ARM PCs is the big deal. “In the spirit of the Dev Channel, this capability is still in development and will continue to improve in both compatibility and performance over time, so some of the apps you try running in emulation may not work initially,” the Windows Insider team explained today.

To test x64 app emulation, Microsoft recommends to do so on the Surface Pro X, the Lenovo Flex 5G, or the Samsung Galaxy Book S, three devices that should provide the best app performance. The Windows Insider team also recommends to install a preview version of the Qualcomm Adreno graphics driver (click here for Surface Pro X, and here for the Lenovo and Samsung devices), as well as a preview version of the ARM64 C++ redistributable to support running both ARM63 and x64 C++ applications at the same time.

“In this preview, you can install x64 apps from the Microsoft Store or from any other location of your choosing. You can try key x64-only productivity apps like Autodesk Sketchbook, as well as games like Rocket League. Other apps, like Chrome, which run today on ARM64 as 32-bit apps, can run as 64-bit using the new x64 emulation capability. These apps may benefit from having more memory when run as 64-bit emulated apps,” the Windows Insider team explained today.

Windows 10 on ARM only supported 32-bit app emulation when it shipped a couple of years ago, and these emulated apps also had performance issues. Introducing x64 app emulation on Windows 10 on ARM is a big milestone to improve app compatibility on the platform, though Microsoft is still pushing developers to recompile their Windows apps for the ARM64 architecture.

If you’re on Dev Channel, the 21277 (RS_PRERELEASE) build will be offered as an optional update through the “seeker” experience in Windows Update. If you don’t opt in to install this build, you’ll receive the build 20277 today with the aforementioned fixes and known issues, and you’ll also keep receiving builds from the FE_RELEASE branch in the coming weeks. This isn’t that different from “Skip Ahead” ring that Microsoft used to have in addition to the Fast Ring, though the Windows Insider team is still saying that Dev Channel builds coming from the RE_PRERELEASE and FE_RELEASE are still not matched to a specific Windows 10 release.

It’s not clear if these are going to be the last Insider flights for this year, though the Windows Insider team said today that all Insiders in the Dev Channel will start receiving builds from the RS_PRERELEASE channel after the holidays. After a couple of weeks of minor builds with no new features, things are starting to look more interesting for the Windows Insider program in January.