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What changes in Windows 11 KB5050009 and KB5050021?

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This article has 4 comments.

Microsoft released cumulative update KB5050021 for Windows 11 version 23H2 and cumulative update KB5050009 for Windows 11 version 24H2 on January 14, 2025.

Windows Update screen for Windows 11 version 24H2
Windows 11 version 24H2 updates

In this update,159 vulnerabilities based on CVE numbershas been addressed and security has been improved.

KB5050021 and KB5050009 contain cumulative updates released on December 10, 2024 (KB5048685 and KB5048667) but does not include fixes for known defects.

Some known issues in Windows 11 version 24H2:

Hopefully, the above issue will be fixed in the next update (preview).

Additionally, drivers at risk from Bring Your Own Vulnerable Driver (BYOVD) attacks, i.e. vulnerable drivers, have been added to the list, further strengthening security.

  • Windows Kernel Vulnerable Driver Blocklist File (DriverSiPolicy.p7b)

I don't know the details of the driver that was added this time, but in some environments that have updated to Windows 11 version 24H2, printers that were previously usable may no longer work.deviceThere have been many reports of users being unable to use their devices or applications.

Some devices and applications that worked fine with Windows 11 version 23H2 are expected to stop working properly after installing the 2025/01/14 update.

KB5050021 and KB5050009 should update automatically, but if you haven't updated yet, we recommend making sure you have System Restore enabled so you can restore your system if any issues arise.

How to create, restore, and delete system backups

*KB5050021 and KB5050009 are required updates to fix vulnerabilities in Windows. We do not recommend blocking them carelessly.

2025/01/16:

Microsoft has updated the document (KB ID: 5047288) to state that the IME issue has been fixed in cumulative update KB5050009 for Windows 11 version 24H2.

*This issue has already been resolved in version 23H2 with KB5048685 released on December 10, 2024.

After installing Windows updates released on or after June 25, 2024, you might experience issues when using certain input method editors (IMEs), including Japanese, in applications built on Windows Presentation Foundation (WPF).

WPF applications may stop responding or close unexpectedly if an IME is used when entering characters into application fields. Some actions may cause this issue to occur more easily, such as when characters are entered quickly or when the IME generates additional input dialog boxes. Because this issue has a timing component, it may not occur consistently. Entering characters slowly can reduce the likelihood of encountering this issue.

Microsoft – KB5047288

2025 / 01 / 22:

In certain environments, installation error 0x800f081f may occur when installing cumulative update KB5050009.

KB5050009 installation error 0x800f081f

2025 / 01 / 31:

The following are actual issues that occurred during testing in an environment where KB5050009 was installed on Windows 11 Home Edition.

If you run a batch file that enables "Hyper-V" or "Local Group Policy Editor," installation error 0x800f081f may occur, preventing you from installing future updates.

If you uninstall KB5050009 while the above symptoms are occurring, the following message will appear:メモリ整合性" will automatically be turned "Off" and will no longer be able to be turned "On."

And when I try to install KB5050009 again, I get installation error 0x800f081f.

In this situation, currentlySystem restoreThere is no way to recover other than returning to the state before "Hyper-V" or "Local Group Policy Editor" was enabled.

*A clean install will definitely solve the problem, but this is a problem that can be solved by system restore.

I wanted to try it with Windows 11 version 23H2, but after installing "Hyper-V" version 24H2 was automatically installed, so I was unable to check.

Windows troubleshooting Windows Update issues
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Person who wrote this article

wenbang's avatar wenbang

Driven by questions arising from my daily PC use and the desire to "do more," I have been pursuing self-study in Windows since around 2008. I am sharing the "aha!" techniques and solutions I discovered through trial and error with the sole purpose of helping you in your PC life.

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Comment:

Comment list (4)

  • After installing KB5050009, the days of the week I added to the bottom right corner disappeared again, so I reset them.

    This time, the sfc /scannow and DISM commands didn't seem to cause any problems, but when I tried to enter safe mode afterwards, a blue screen occurred. I'm not sure if this was related to the fact that I had just run Windows Update and Background Intelligent Transfer Service troubleshooting. The Windows Update troubleshooting still works.
    Last year, after updating a Microsoft app from the Microsoft Store, I tried to enter safe mode and experienced a blue screen of death, which is a similar symptom. After that, I rebooted and shut down, but the power button light didn't go off, and pressing the default button on the BIOS screen and saving and restarting solved the issue, too.
    I think I may have solved it, but it still feels unstable.

    The other day, I got a blue screen when updating BlueStacks. It seemed like there was no problem if I uninstalled it and then installed it again, but I ended up uninstalling it again.

    I think this is separate from the latest update, but a few days ago, a frame started appearing when selecting items on the taskbar in the bottom right. I think the purpose is to emphasize the item, but I wonder if there was a change in the specifications.

    Reply

    • Thank you for your comment, Siden.

      After installing KB5050009, some settings were reset to the defaults, which is probably why the days of the week you added disappeared.
      It is unclear whether the occurrence of a blue screen is related to troubleshooting, but analyzing the dump file (MEMORY.DMP) in the C:\WINDOWS\Minidump folder created after the blue screen occurs may help identify the cause.

      I didn't mind the borders that appeared when selecting items such as the taskbar, but the borders were still displayed in the same way before installing KB5050009.

      Reply

      • Thank you very much.
        I checked C:\WINDOWS\Minidump, but it was empty. Maybe it was deleted by Disk Cleanup? Anyway, I don't know the details, and it doesn't seem to have happened again so far.

        Reply

        • Dear Siden,

          If "Minidump file on system errors" is checked in Disk Cleanup, the dump file (MEMORY.DMP) will be deleted.
          If it hasn't recurred then there doesn't seem to be a problem.

          Reply

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