Windows 10 Insider Preview Build 21292 Carries A Sad Surprise For Arm PCs

Windows 10
Do you think Microsoft might be feeling the heat from Apple to improve the Windows 10 experience on Arm hardware, now that Apple has released its M1 chip? Maybe, maybe not. Either way, Microsoft last month released a preview build of Windows 10 on Arm to Insiders in the Dev channel, which added the ability to run x64 apps in emulation. However, a subsequent cumulative update breaks the experience.

Windows 10 Insider build 21292 in the Dev channel is the one that adds support for x64 app emulation. It arrived in the second week of December 2020, and bolstered the functionality of Arm64 devices like the Surface Pro X and Lenovo Flex 5G. Those have been off limits up to that point, as when Arm64 devices first landed, they were limited to native Arm64 code and traditional x32 applications in emulation.

That is still the case in the public arena, though Microsoft is hard work adding support for x64 app emulation, with the help of Insiders. If you are one of them, you should probably avoid the latest cumulative update that is available.

"KNOWN ISSUE: After installing build 21292.1010 (KB4601937), x64 emulation on Arm PCs will not work. There is an issue with the way the update is installed that breaks this functionality. As a workaround, you can uninstall KB4601937 to get x64 emulation working again on your Arm PC," Microsoft's Brandon LeBlanc stated in a blog post.

The good news is, if you are an Insider and already downloaded the update, figuring it would be rather benign, you can simply uninstall KB4601937 and restore x64 emulation on your Arm PC. There is even better news, though—you won't be missing out on anything by removing it. Why not?

"This update does not include anything new and is designed to test our servicing pipeline," LeBlanc explains.

In other words, Microsoft is simply testing its ability to continue rolling out cumulative updates, with the whatever under-the-hood changes it has made. As for the core build itself (without the cumulative update installed), one of the fixes is better support for x64 emulation on Arm64 devices. Users had reported that certain x64 apps would crash, and the latest build addresses that problem specifically with Zwift, Serif Affinity Photo, and Your Phone. It also fixes an issue that was cause blank pages in Steam.