September 2021 Patch Tuesday is here, Windows 10 21H1 build 19043.1237 is live

Windows Update
Windows Update (Image credit: Windows Central)

What you need to know

  • September 2021's Patch Tuesday is here.
  • Recent versions of Windows 10 can look forward to cumulative update KB5005565.
  • These versions include 21H1, 20H2, and 2004, as well as the now-in-testing 21H2.

September 2021's Patch Tuesday is here. For Windows 10 version 21H1, 20H2, 2004, and 21H2 (for the Windows Insiders who are testing it) cumulative update KB5005565 is here. Windows 10 version 1909 is also getting a cumulative update, KB5005566. KB5005566 features the same fixes as KB5005565.

If you want a full round of the month's security updates, you can find the extensive list over at Microsoft's site. As for key changes outside the laundry list of security items, Microsoft's has only designated one as a noteworthy highlight:

  • Addresses an issue that causes PowerShell to create an infinite number of child directories. This issue occurs when you use the PowerShell Move-Item command to move a directory to one of its children. As a result, the volume fills up and the system stops responding.

This Patch Tuesday brings the build numbers of Windows 10 21H1, 20H2, and 2004 up to 19043.1237, 19042.1237, and 19041.1237. It's not the most content-stacked Patch Tuesday to ever pass, but as is always the case with Windows, unexciting security updates are a predictable, welcome inclusion given how many threat actors target the operating system family's various iterations.

With that in mind, there are those who don't put a premium on Windows updates. In response to the recent news that unsupported PCs on Windows 11 have a dicey future ahead with regards to said updates, a majority of readers on Windows Central still went ahead and said they'd risk it for the biscuit and enjoy the new OS on their unsupported device.

Robert Carnevale

Robert Carnevale is the News Editor for Windows Central. He's a big fan of Kinect (it lives on in his heart), Sonic the Hedgehog, and the legendary intersection of those two titans, Sonic Free Riders. He is the author of Cold War 2395. Have a useful tip? Send it to