Windows 10 ESU Licensing Preparation Package (KB5126256) is installed

Wolfgang Dedekind 0 Reputation points
2026-10-22T11:55:26.53+00:00

ESU does not run ? requ. are all installed

I got the german answer

"Wir können Sie im Moment nicht für erweiterte Sicherheitsupdates registrieren. Schließen Sie das Fenster und versuchen Sie es erneut."

Windows for home | Windows 10 | Extended Security Update (ESU)
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  1. Vikki-T 14,115 Reputation points Microsoft External Staff Moderator
    2026-10-23T06:24:20.1766667+00:00

    Hello Wolfgang Dedekind,

    The German message means: “We can’t enroll you in Extended Security Updates at the moment. Close the window and try again.”

    Since KB5126256 is already installed, the preparation package appears to be in place. However, this package only prepares Windows for ESU enrollment; it does not complete the enrollment by itself.

    Please open Settings > Update & Security > Windows Update, install any remaining updates, and restart the PC even if Windows does not currently request one. Then reopen the ESU enrollment window and try again.

    As this is Windows 10 Home, I would not recommend using the ESU MAK activation commands shown above, because those instructions are intended for commercial licensing scenarios. If the same message continues to appear after Windows is fully updated and restarted, please contact Microsoft Support so they can check the consumer ESU enrollment status for your Microsoft account and device.

    Note: Windows 10 reached end of support on October 14, 2025. ESU provides eligible enrolled devices with critical and important security updates for a limited period, but it does not include new features or restore full Windows 10 support. If your device is eligible, upgrading to Windows 11 remains the recommended long-term option.

    You can also review Microsoft’s official information about KB5126256 and its ESU prerequisites. Thank you so much for your understanding.     

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

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  2. AI answer

    2026-10-22T11:55:46.67+00:00

    KB5126256 alone does not start ESU. It only prepares Windows 10 version 22H2 for ESU licensing and enrollment. The device must still be enrolled in the ESU program to receive security updates.

    For this scenario, check these items in order:

    1. Confirm the device is on Windows 10, version 22H2.
    2. Confirm a security update released on or after October 14, 2025 is already installed. KB5126256 must be installed after that update.
    3. Restart the device. The preparation package requires a restart.
    4. Try the enrollment again later. A similar Windows 10 ESU enrollment issue has been reported where enrollment can keep spinning or fail temporarily even when prerequisites are met.
    5. If ESU key activation is being used, verify the key is installed and activated:
      • Open an elevated Command Prompt.
      • Run slmgr /dlv all
      • Verify the ESU key shows as licensed.
    6. If updates still do not install, install and activate the ESU key again using an elevated Command Prompt:
      • slmgr /ipk <ESU key>
      • slmgr /ato <Activation ID>
    7. If installation or activation fails with prerequisite-related errors:
      • If the update says not applicable, verify the package matches the OS edition and architecture, then restart and try again.
      • If activation returns 0xC004F050, verify all ESU prerequisite updates are installed successfully, confirm the correct key is being used, then restart and try again.

    If the problem continues after the restart and prerequisite checks, collect C:\Windows\Logs\CBS\CBS.log and contact Microsoft Support.

    References:

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