On Windows 10, Windows Update may sometimes offer you an “Optional Quality Update.” Unlike other updates, Windows won’t automatically install these—so what exactly are they? Should you install them?
Windows Update Won’t Automatically Install These
An “optional quality update” is a Windows update that you don’t have to install immediately. These never include security fixes—if an important security patch is available, Windows Update will install it without waiting.
However, some updates are optional. These fix stability issues and other problems in Windows. Some of these may be optional hardware driver updates. You have the choice of whether or not to install these—it’s up to you.
What Is a “Cumulative Update Preview”?
One of the most common optional quality updates is a “cumulative update preview.” Microsoft releases cumulative updates once a month on Patch Tuesday, which is the second Tuesday of each month.
These updates bundle a large number of fixes for various problems in a big package. Rather than releasing a slow drip of updates throughout the month, Microsoft bundles them all into one big update.
These packages are called “cumulative” because they include all the fixes from previous months in a single package. For example, if you haven’t turned a computer on in several months, a single month’s cumulative update will include all the fixes from previous months. Windows only has to install one big update, saving you time and avoiding unnecessary reboots.
Microsoft doesn’t hold every fix for the cumulative update. For example, important security updates are released immediately without waiting.
Near the end of most months, Microsoft offers a “cumulative update preview” in Windows Update. (Microsoft generally skips late December’s cumulative update preview.) These preview updates include all the fixes that will be released to everyone in non-optional form on the next Patch Tuesday.
For example, in November of 2020, Microsoft released the 2020-11 Cumulative Update Preview on November 30, 2020. If you didn’t choose to install it, your PC would get the final, non-preview version of the “cumulative update” a few weeks later on the next Patch Tuesday—in our example, that’s December 8, 2020.
These Are “C” and “D” Updates
By the way, if you’re familiar with Windows update terminology, you may know these preview cumulative updates by a different name. Microsoft calls these “C” and “D” updates, depending on whether they’re released in the third or fourth week of every month.
The final stable cumulative update released the next month is known as a “B” update. That’s because it’s released in the second week of the month.
Preview Updates Make You a Software Tester
The word “preview” is a hint that you’re helping Microsoft test the update by installing it. Microsoft is counting on a large number of people noticing the update and choosing to install it. Microsoft calls people who visit the Windows Update page and choose to manually install updates “seekers” who are looking for updates.
By installing the update only for these motivated “seekers,” Microsoft can see whether the update causes problems on a variety of Windows 10 PCs. If it does, Microsoft can hit the pause button or fix the update before it rolls out to everyone on Patch Tuesday.
Think of these monthly preview updates as similar to Microsoft’s Windows Insider Program. People who want to test new versions of the software can get it early, while people who aren’t eager to install new Windows updates can wait.
Should You Install the Optional Update?
If you’re experiencing a problem with your PC, installing the optional update is a way to get a fix for that issue weeks early. They’re usually pretty stable and are much more stable than early builds of Windows 10 intended for people who opt into the “Windows Insider” testing program.
However, if you’re not experiencing an issue with your PC, you don’t need to install the optional quality update—not unless you want to help Microsoft test it. If you wait a few weeks, your PC will get the same fixes after they’ve undergone additional testing.
How to Install Optional Quality Updates
To check for optional quality updates, head to Settings > Update & Security > Windows Update. Click “Check for Update” to check for available updates. Windows will install any mandatory updates (including security updates and non-optional cumulative updates) automatically.
If an optional quality update is available, you’ll see a message saying so below the “Check for Updates” button. Click “Download and Install” if you want to install it on your PC.
You can also click “View all optional updates” to see all the optional updates you can install. For example, this list likely includes optional driver updates that might help if you’re experiencing a problem on your PC. However, this button will only appear if optional updates are actually available for your PC.
If you experience a problem with an update, you can head to Settings > Update & Security > Windows Update > View Update History > Uninstall Updates to remove the update from your Windows 10 PC.