Microsoft’s Windows 10 2004 KB4571756 patch pushed on 8th September breaks Windows Subsystem for Linux 2 (WSL2); Here is how to fix it
If you already don’t know, Microsoft pushed a set of cumulative patches through its September Patch Tuesday program for different Windows 10 versions including Windows 10 1903, 1909, and 2004. KB4571756 patch is one of the patches that have been pushed through to the Windows 10 2004 version. The KB4571756 patch pushes Windows 10 2004 up to build number 19041.508.
Since the patches were getting installed on Windows 10 2004 version PC/laptops, many users have reported that the KB4571756 patch breaks the Windows Subsystem for Linux 2 (WSL2). Even on Windows 10 forums, multiple Windows 10 version 2004 users are reporting they’re unable to launch WSL2 after installing Tuesday’s security update aka KB4571756 patch.
WSL2 has emerged as a very popular tool for Windows users who also love Linux. WSL2 provides a full Linux kernel, system-call support for all Linux apps, including Docker, FUSE, rsync, and more. The second version of WSL was shipped with Windows 10 version 2004, aka the May 2020 Update. Since then, Microsoft has also made WSL2 available for Windows 10 1903 and 1909 versions.
A user on GitHub has reported that after installing KB4571756 his WSL2 crashed and gave an ‘Element not found’ error. It also showed gave his ‘Process existed with code 4294967295’ message.
Fix for WSL2 crashing on Windows 10 2004 versions updated with KB4571756
Though many users have reported WSL2 crash after updating their Windows 10 2004 PC/laptop with KB4571756 patch, Microsoft is yet to officially acknowledge this issue. The issues seems to stem from a service called Hyper-V. Since Windows 10 2004 Home edition doesn’t have Hyper-V, these users don’t have any problem with running WSL2 after the KB4571756 patch is installed.
As for other users, as of yet there is no workaround to get the WSL2 to work but uninsalling the KB4571756 makes the bug go away. Several other Windows 10 2004 users reported on GitHub that uninstalling KB4571756 and reverting to build number 19042.487 allows WSL2 to start again.
You can refer to this article to uninstall the KB4571756 patch and get your WSL2 running again on your Windows 10 2004 PC/laptop.