How to block the Windows 10 May 2021 Update, version 21H1, from installing

Windows 10 21H1 is a minor update, but it’s still wise to opt out of beta testing it. Here’s how to keep the new release off your system for now.

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Editor's note: As of May 18, Microsoft has officially released Windows 10 21H1 — but it’s not too late to prevent it from installing on your machine.

It’s that semi-annual time again when a new Windows 10 feature update is imminent — and when you need to decide whether or not you want to participate in its unpaid beta testing process. Microsoft makes it easy for you to opt into beta testing, but not as easy to opt out.

Sure, Microsoft says its Windows Insider program is its beta testing program for new releases of Windows 10, but I honestly consider that more of a mechanism for marketing new features. It’s only when a new Windows 10 feature release is offered up to the public — and begins to run on all of the different hardware that we have out here in Windowsland — that the true testing begins.

Often people question the need for twice-annual feature releases, and in most cases, it’s hard to point to any feature that the vast majority of Windows users need. Rather, the feature update process ends up providing a “clean up” of your Windows 10 machine and ensures its future health. Often I’ve used the feature release process to repair a Windows 10 machine that refused to install updates and was throwing off error messages.

In addition, the installation of a feature update will extend the support window for your machine. For example, Windows 10 version 1909 stops being supported on May 11, 2021. Installing Windows 10 2004 immediately extends the support to December 14, 2021. If you are on the 20H2 version of Windows 10, it’s supported until May 10, 2022.

But while installing feature updates helps sustain a PC in the long run, brand new Windows 10 feature releases often have stability and compatibility issues. For that reason, it’s best to keep them off your production systems for at least the first several months they’re available.

I use the release of a new feature update to be the sign that I need to ensure that all of my main computers are on the prior release. I prefer to stay one release behind, as it typically provides me with a stable system, and I’m able to identify what issues I may face.

Based on the prior feature release processes, for example, I know that at the office I will need to deal with repairing PDF printers that will be impacted by the feature update. I use various software products from Intuit, and I have to use the its PDF repair tool to fix up my QuickBooks after the feature update process. I also have older client backup software that has to be uninstalled and reinstalled in order to continue to work. So I always want to control the installation of any feature release on my workstations so I can plan on fixing these two follow-up issues on my schedule.

This spring’s Windows 10 release deviates from the tick-tock model we’ve seen for Windows 10 feature updates over the past couple of years. Normally, the update in the first half of the year contains major changes; the update in the second half of the year holds only minor changes and bug fixes. But this year’s “tick” release, 21H1, doesn’t contain much in the way of new features, especially for home users and consumers. In other words, there’s no reason to upgrade immediately.

Fortunately, Microsoft doesn’t cram each new version of Windows down your throat like it used to. Now it’s offered up to your system, and you have to click on the box to start the install process. In fact, you may not see the new release in Windows Update as soon as Microsoft announces its availability; the company pushes it out to various systems over time, with zero communication as to who gets it when. But if you want to make sure you aren’t first in the line to install this release, here’s how to ensure you aren’t accidentally swept up in an unwanted upgrade.

Step 1. What version are you running?

The method for blocking unwanted version upgrades varies greatly depending on which version of Windows 10 you’re running. To find out, click Start > Settings (the gear icon) > System, and on the left side at the bottom, click About.

You’ll see something like the screenshot below. Take note of both the edition (Pro, Home, Education, Enterprise) and the version.

win10 about 20h2 IDG

Checking the Windows 10 edition and version.

If your computer is connected to a network that has an update server (such as WSUS or SCCM or other third-party patching tool like PDQ Deploy), you don’t have any control over your version — the network administrator or the consultant hired by your firm gets to sweat this one out.

Your firm may be using a Microsoft cloud product called Intune to control your updates; if that’s the case, you won’t have control over them. You may wish to reach out to the IT department to see what their plans are for the rollout of the feature release.

Step 2. If you’re on version 1909 or earlier, move to a later version ASAP.

For Home and Pro customers, the last security update for Windows 10 version 1909 was on May 11, 2021. That means starting in June, that version will no longer receive security updates.

You must move on from 1909. As these releases reach end of support, you should start seeing increasing notifications that your machine is ready for 20H2.  At this point 20H2 has been tested well enough that I recommend updating to that version at this time.

The best approach is to download a copy of 20H2 from the Windows ISO site. First back up everything, then follow the steps in the Windows Update Assistant. You could alternatively go to Windows Update (Start > Settings > Update & Security) and click Download and install for version 20H2, but using the Windows Update Assistant lets you save a clean copy of the 20H2 ISO for future use.

Whatever you do, move quickly: When the 21H1 release becomes final, the Windows Update Assistant (as well as Windows Update on your computer) will begin to offer up the 21H1 release instead of 20H2.

Step 3. If you’re on version 20H2, don’t click that link.

Both Home and Pro users running Windows 10 version 2004 or 20H2 will eventually see a Windows Update notice (Start > Settings > Update & Security) like the one in the screenshot below, saying that 21H1 is ready to be downloaded and installed.

win10 21h1 download install IDG

Don’t click the "Download and install" link!

If you want to avoid installing Windows 10 version 21H1, don’t click the Download and install link. And always remember — you don’t want to click Check for updates, as this will offer up optional .NET updates on your system that you don’t want installed.

Step 4. There is a better way (for some) to stay away from 21H1.

For those who are comfortable with editing the Windows registry (and have admin priveleges to so), there is a more sure-fire way to defer 21H1. Using a registry setting called TargetFeatureRelease, you can ensure that you aren’t even offered 21H1.  

Here’s the manual process:

  1. Before editing the registry, you should always back up the registry and your computer in case something goes wrong.
  2. Open the Registry Editor by typing regedit in the Windows search box and clicking on Registry Editor.
  3. Find the following registry key (i.e., the WindowsUpdate key): HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate
  4. Right-click the key; select New and then DWORD from the fly-out menu.
  5. Enter the name TargetReleaseVersion.
  6. Set the value to 1 (one).
  7. Right-click again on the WindowsUpdate key; select New > String value.
  8. Enter the name TargetReleaseVersionInfo.
  9. Set the value to your desired target version: in this case, 20H2.

If the WindowsUpdate key is not visible in the Registry Editor, use these few steps first.

  1. Open the Registry editor.
  2. Find the following registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows
  3. Right-click on the key, then select New and Key.
  4. Enter the name of the key, WindowsUpdate.
  5. Follow the steps above.

You can alternatively download a registry key that automates this process from the AskWoody website. (Feel free to open up the .reg file in Notepad and view it first before installing it.)

When you’re ready to install 21H1 down the line, you can go back into the Registry and change the TargetReleaseVersionInfo value to 21H1 or download the 21H1 registry key from AskWoody.

Get ready for 21H1 now.

While we still don’t know exactly when Windows 10 21H1 will be released, it’s likely to be soon. Take the time now to prepare your machine by ensuring you have a backup and setting in place deferrals for this upcoming feature release.

Moving forward, keep an eye out for any conflicts with 21H1 by checking with your key software vendors to ensure that there are no side effects. If you are not using Microsoft Defender, be sure to check on your antivirus vendor’s website to ensure it supports 21H1. Only when you know your systems are compatible with 21H1 should you consider moving to it.

As always, we follow all things patches on AskWoody.com.

This article was originally published in October 2017 and most recently updated in May 2021.

Copyright © 2021 IDG Communications, Inc.

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