RELATED: What Is Patch Tuesday for Windows, and When Is It? These Are “C” and “D” Updatesīy the way, if you’re familiar with Windows update terminology, you may know these preview cumulative updates by a different name. 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. 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.įor example, in November of 2020, Microsoft released the 2020-11 Cumulative Update Preview on November 30, 2020. For example, important security updates are released immediately without waiting. Microsoft doesn’t hold every fix for the cumulative update. Windows only has to install one big update, saving you time and avoiding unnecessary reboots. 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.
These packages are called “cumulative” because they include all the fixes from previous months in a single package.