Windows 10 September Update KB5122878 causes No Operating System found on Acer laptop

John Price 65 Reputation points
2026-09-26T15:11:05.03+00:00

KB5122878 after many reinstallations of Windows 10 ESU consistently crashes a friends Acer laptop. Currently I have left this laptop not enabling ESU updates (KB126256) as I have failed to stop the KB5122878 update installing many times. Am I missing something? Can I stop this one killer update downloading and installing? I have already made the registry edit to stop WindowsUpdate, although I am not confident it works. Any suggestions to save this laptop as safely as possible, currently relying on Malwarebytes.

Windows for home | Windows 10 | Windows update

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SD - IA 180.3K Reputation points Independent Advisor
2026-09-30T14:58:27.5366667+00:00

I see, I think your problem is resolved now and no action is required from your end.

Wanted to ask if you have any other questions?

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Answer accepted by question author
SD - IA 180.3K Reputation points Independent Advisor
2026-09-30T08:18:15.7333333+00:00

I have now installed the rogue KB5122878 🙂

That is actually the latest update :)

By any chance, are you from the EU? That may explain why enrollment in ESU was not needed.

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SD - IA 180.3K Reputation points Independent Advisor
2026-09-29T16:43:10.81+00:00

I also did research on the issue, and it seems that you are right :( There are some specific models before 2016 which aren't compatiable, sorry :(

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  1. SD - IA 180.3K Reputation points Independent Advisor
    2026-09-26T15:48:42.0933333+00:00

    Hi,

    Please supply the following Information.

    Right-click the Start button and Choose the Run option

    Type in msinfo32

    Press enter.

    Take a screenshot of the System Summary window and post it in the next reply.

    I look forward to your response and am eager to collaborate until we find a solution.

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  2. John Price 65 Reputation points
    2026-09-26T15:41:01.2766667+00:00

    Unfortunately I dont even have an Windows 10 operating system and have had to reinstall from scratch.

    I just dont want to install it, my only safe option is not to enable ESU, so the laptop is stuck in September 2025.

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