Microsoft Fixed WSL2 Bug

October 4, 2020

Our second story is a sad one for many Engineers, but ends on a happy note. The September 8th round of Windows Updates had a nasty bug in it that broke the Windows Subsystem for Linux 2 for users running Windows 10 version 2004. According to a report from Bleeping Computer, the Microsoft KB4571756 Security Update introduced a flaw that prevented users from launching WSL2 from the command prompt. When attempting to do so, the flaw would cause an error that read, “Element not found” or ” Process existed with code 4294967295″. Luckily, there is now a fix in the form of another patch from Microsoft that dropped on October 1st. Our fellow Engineers can install the Windows 10 2004 KB4577063 Non-Security Preview Cumulative Update to fix the issue. If updates cannot be applied, many users reported that by uninstalling KB4571756 they were able to restore WSL2 functionality. Please keep in mind, since Windows Updates are now cumulative it will likely roll back the 20 critical security patches that came with the update.

DJs Take

It’s sad, but it seems that operating systems are so complex these days that flaws like this cannot be avoided. Luckily, Microsoft turned this around in less than a month. It appeared to only hinder users with Hyper-V capabilities, which WSL2 uses, according to some reports in online forums. So, as most Engineers will know, do not use WSL or WSL2 for running code in production situations. Use an actual Linux Kernel. Additional information can be found in a link in our show notes.

Ian’s Take

I love Windows Subsystem for Linux 2 and am pleased that this project continues to move forward. What troubles me is Microsoft’s testing methodology. As Windows becomes more complicated and does more things behind the scenes, we continue to see update issues in their codebase.  Now granted, the Microsoft Windows team has a very tough task ahead of them with these types of project which is why they continue to make Windows modular.  The Windows Insider Program used to provide help with this type of issue but has now proven basically useless. 

“We are transitioning and converting our current ring model, based on the frequency of builds, to a new channel model that pivots on the quality of builds and better supports parallel coding efforts,” Langowski writes. “In addition to this change, Insiders will also find similar offering names and expectations across Windows and Office programs and soon Microsoft Edge and Microsoft Teams.”
– Amanda Langowski

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