2026-08 Security Update (KB5121003) (26200.9168) not installing despite following lots of tips.

Grady 0 Reputation points
2026-08-25T09:07:27.4033333+00:00

I just obtained a brand new HP laptop and am completely unable to install this update

Order of events:

  1. I download the update (no problems here)
  2. it prompts for a reboot
  3. upon reboot it somewhat "gives up" and just loads me into a boot screen where I just end up staring at the HP logo forever
  4. I end up holding down on the power button eventually leading to the system to shut down and start up again
  5. upon start up it begins "diagnosing" then "repairing" and eventually undoing the update bringing me back to square one What I have tried:
    1. I have ran all 3 of the dism commands
    2. done ,system--recovery and then "fix problems using windows update"
    3. manually downloading it. Leads to the same issues listed above. Are there any other possible fixes to avoid what's going on? Is Microsoft aware of this issue and working on a fix? If they are, and there are no other solutions I will most likely pause this update until then. If not, well I really have no clue. This is a brand new laptop and I've already returned the previous one for the EXACT same reason.
Windows for home | Windows 11 | Windows update

6 answers

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  1. Igor 0 Reputation points
    2026-08-27T00:56:53.96+00:00

    I’m having the same issue on a brand-new HP OmniBook X Flip 16 (16-cc0013dx) with:

    • AMD Ryzen AI 5 430
    • 16 GB RAM
    • 512 GB SSD
    • Windows 11 25H2

    The problem happens specifically when installing 2026-08 Security Update KB5121003 (26200.9168).

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  2. John DeV 168.9K Reputation points Independent Advisor
    2026-08-26T22:19:32.97+00:00

    Based on the reports in this thread, it appears that other users are experiencing similar installation issues with KB5121003, particularly on some HP systems. Since you have already tried the recommended troubleshooting steps, I recommend reporting the issue through the Feedback Hub app so Microsoft can investigate and collect additional diagnostic data.

    For now, you can also pause Windows Updates for up to one week and check again later for a newer update or a Microsoft-provided fix.

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  3. Bulldog 4,040 Reputation points
    2026-08-26T20:04:42.8666667+00:00

    If a brand new computer purchased from one of the major manufacturers can't install a standard update to Windows, waste no time: Contact the manufacturer. A brand new computer should work perfectly. Take advantage of your warranty - you paid for it!

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  4. AI answer

    2026-08-25T09:07:49.0566667+00:00

    Since DISM, the Windows Update repair option, and manual installation were already tried, the remaining supported steps are:

    1. Check free space on the system drive.
      • Windows needs at least 16 GB free for a 32-bit OS or 20 GB for a 64-bit OS to upgrade.
    2. Temporarily remove any third-party antivirus or security software.
      • This can block updates.
      • Make sure reinstall information and any product keys are available before uninstalling.
    3. Update third-party drivers from the laptop manufacturer.
      • Since the system hangs during reboot at the HP logo, an incompatible driver is a known cause of update failures.
      • Check HP’s support site for updated drivers and installation instructions, then try Windows Update again.
    4. Run Windows Update again after those checks.
      • Go to Start > Settings > Windows Update > Check for updates.
    5. If the update still fails, reset the Windows Update components.
      • Warning: these are advanced command-line steps and require administrator permissions.
      • Open Command Prompt as administrator and run these commands one at a time:
    net stop bits
net stop wuauserv
ren %systemroot%\softwaredistribution softwaredistribution.bak
ren %systemroot%\system32\catroot2 catroot2.bak
net start bits
net start wuauserv
    • Then restart the PC.
    1. Check the drive for file-system errors.
      • Open Command Prompt as administrator and run:
    chkdsk /f C:
    • Restart when prompted.
    1. Perform a clean restart of Windows.
      • A clean restart starts Windows with minimal drivers and startup programs and can help identify software conflicts that block updates.
    2. If the device keeps entering repair/rollback after every attempt, use Windows Recovery Environment options.
      • Boot into Automatic Repair.
      • Go to Advanced options.
      • Try System Restore first if available.
      • If that is unavailable, try Startup Repair.
      • If recovery options do not resolve it, Reset this PC with Keep my files is the next supported path.

    The provided material does not confirm that Microsoft has acknowledged a specific issue with KB5121003 or that a fix is in progress.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

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  5. John DeV 168.9K Reputation points Independent Advisor
    2026-08-25T09:47:11.17+00:00

    Hi, good day!

    Since you have already tried the DISM repairs, Fix problems using Windows Update, and manually installing KB5121003, I would recommend trying an in-place repair upgrade of Windows 11 as the next step. It will definitely help in resolving update errors. Performing this can repair broken operating system files while your personal files, settings and installed applications will not be removed.

    Few things to check on the PC

    Unplug all external peripherals except for the Mouse, Keyboard, and LAN cable before starting

    Disable or uninstall any third-party Antivirus program to prevent it from interfering with the upgrade

    https://learn.microsoft.com/en-us/answers/questions/4252110/how-to-run-in-place-upgrade-in-windows-11?forum=windows-all&referrer=answers

    I look forward to receiving your update and I'm willing to collaborate with you till we resolve the issue. Do keep me informed by clicking "Add comment" below.

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