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Today is Patch Tuesday, which is the second Tuesday of the month and the day that Microsoft releases updates for all supported versions of Windows. For consumers on Windows 10, that only includes two different updates, one for version 1909 and one for versions 2004 and 20H2. In fact, when support for version 1909 ends in May, there's just going to be the one cumulative update that fits versions 2004, 20H2, and the upcoming 21H1 update.

For those on Windows 10 versions 20H2 (including Windows Insiders) and 2004, you'll get KB4601319, bringing the build number to 19042.804 and 19041.804, respectively. You can manually download it here, and these are the highlights:

  • Updates to improve security when using input devices such as a mouse, keyboard, or pen.
  • Updates for verifying usernames and passwords.

Here's the full list of fixes:

  • Addresses a possible elevation of privilege vulnerability in the win32k component.
  • Addresses an issue that might damage the file system of some devices and prevent them from starting up after running chkdsk /f.
  • Security updates to the Windows App Platform and Frameworks, Windows Apps, Windows Input and Composition, Windows Cloud Infrastructure, Windows Management, Windows Authentication, Windows Fundamentals, Windows Cryptography, Windows Virtualization, Windows Core Networking, and Windows Hybrid Cloud Networking.

There's also a known issue to be aware of in this update:

Symptom Workaround

System and user certificates might be lost when updating a device from Windows 10, version 1809 or later to a later version of Windows 10. Devices will only be impacted if they have already installed any Latest cumulative update (LCU) released September 16, 2020 or later and then proceed to update to a later version of Windows 10 from media or an installation source which does not have an LCU released October 13, 2020 or later integrated. This primarily happens when managed devices are updated using outdated bundles or media through an update management tool such as Windows Server Update Services (WSUS) or Microsoft Endpoint Configuration Manager. This might also happen when using outdated physical media or ISO images that do not have the latest updates integrated.

Note Devices using Windows Update for Business or that connect directly to Windows Update are not impacted. Any device connecting to Windows Update should always receive the latest versions of the feature update, including the latest LCU, without any extra steps.

If you have already encountered this issue on your device, you can mitigate it within the uninstall window by going back to your previous version of Windows using the instructions here. The uninstall window might be 10 or 30 days depending on the configuration of your environment and the version you’re updating to. You will then need to update to the later version of Windows 10 after the issue is resolved in your environment. Note Within the uninstall window, you can increase the number of days you have to go back to your previous version of Windows 10 by using the DISM command /Set-OSUninstallWindow. You must make this change before the default uninstall window has lapsed. For more information, see DISM operating system uninstall command-line options.

We are working on a resolution and will provide updated bundles and refreshed media in the coming weeks.

If you're still on Windows 10 version 1909, you're going to get KB4601315, bringing the build number to 18363.1377. You can manually download it here, and these are the highlights:

  • Updates to improve security when using input devices such as a mouse, keyboard, or pen.
  • Updates for verifying usernames and passwords.

Here's the full list of fixes:

  • Addresses a possible elevation of privilege vulnerability in the win32k component.
  • Security updates to Windows App Platform and Frameworks, Windows Apps, Windows Input and Composition, Windows Cloud Infrastructure, Windows Management, Windows Authentication, Windows Fundamentals, Windows Cryptography, Windows Virtualization, Windows Core Networking, and Windows Hybrid Cloud Networking.

This one also has a couple of known issues to be aware of:

Symptom Workaround

System and user certificates might be lost when updating a device from Windows 10, version 1809 or later to a later version of Windows 10. Devices will only be impacted if they have already installed any Latest cumulative update (LCU) released September 16, 2020 or later and then proceed to update to a later version of Windows 10 from media or an installation source which does not have an LCU released October 13, 2020 or later integrated. This primarily happens when managed devices are updated using outdated bundles or media through an update management tool such as Windows Server Update Services (WSUS) or Microsoft Endpoint Configuration Manager. This might also happen when using outdated physical media or ISO images that do not have the latest updates integrated.

Note Devices using Windows Update for Business or that connect directly to Windows Update are not impacted. Any device connecting to Windows Update should always receive the latest versions of the feature update, including the latest LCU, without any extra steps.

If you have already encountered this issue on your device, you can mitigate it within the uninstall window by going back to your previous version of Windows using the instructions here. The uninstall window might be 10 or 30 days depending on the configuration of your environment and the version you’re updating to. You will then need to update to the later version of Windows 10 after the issue is resolved in your environment. Note Within the uninstall window, you can increase the number of days you have to go back to your previous version of Windows 10 by using the DISM command /Set-OSUninstallWindow. You must make this change before the default uninstall window has lapsed. For more information, see DISM operating system uninstall command-line options.

We are working on a resolution and will provide updated bundles and refreshed media in the coming weeks.

Microsoft and Discord have found incompatibility issues with some games using Direct3D 12 when the in-game overlay feature of Discord is enabled. When attempting to open affected games you might receive an error, or the game might close silently.

To mitigate this issue, you can turn off the in-game overlay in settings within the Discord app.

This issue is now resolved in an update to the Discord app. To verify you're on the latest version, right click on the Discord icon in the notification area and select "Check for updates…". If there are updates to install, it should install automatically but you might need to select the arrow icon in the upper right corner of the app to install the updated version. There is no update for Windows needed to resolve this issue.

Finally, here are the updates available for versions that aren't supported for consumers, but are supported under different scenarios.

Version KB Build Download Support
1809

KB4601345

17763.1757 Update Catalog Enterprise and Education SKUs
1803

KB4601354

17134.2026 Update Catalog
1703

KB4601330

15063.2642 Update Catalog Surface Hub only
1607

KB4601318

14393.4225 Update Catalog Long-Term Servicing Branch
1507

KB4601331

10240.18842 Update Catalog

As usual, these are mandatory updates. That means that if you don't go and install them through Windows Update now, they'll be installed automatically at some point.