error 0x800703fa

toni 0 Reputation points
2026-09-06T13:17:42.07+00:00

I've tried updating my windows, but it gets stuck at 9% and has to roll back changes. I have tried pretty much everything i could find on the internet.

my win ver is: 19045.3803

https://learn.microsoft.com/en-us/answers/questions/5526946/how-to-fix-error-0x800703fa
seems like the exact issue as in here. i've ran mct but it seems to have failed, as i still get the same error. However, in this case they just reinstalled windows, but i'd like to wind a solution where i don't have to do that.

stuck at update KB5066791.
Heres a link to setuplogs from onedrive. If i did it right. Seems like panther and rollback dont have any files in them even when i have them on my c:
https://1drv.ms/u/c/ef76caaa71dc239e/IQC1adyRckUhToKTsjovfqvoAeoORWRYFI1qXeJYVV1hU-0?e=ScSvXz

Windows for home | Windows 10 | Windows update

Answer accepted by question author
Ramesh 180.9K Reputation points Volunteer Moderator
2026-09-10T11:01:49.4133333+00:00

it is also saying i'm missing important security and quality fixes, but i think i read that this may be a false alarm from somewhere.

Is your PC enrolled in the Windows 10 Extended Security Updates | Microsoft Windows program?

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  1. Ramesh 180.9K Reputation points Volunteer Moderator
    2026-09-10T11:00:22.19+00:00

    it is also saying i'm missing important security and quality fixes, but i think i read that this may be a false alarm from somewhere.

    Are you enrolled into the ESU program?

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  2. TaoLi 110.6K Reputation points Independent Advisor
    2026-09-06T14:04:58.2333333+00:00

    Hi

    I checked your SetupLogs.zip. The Panther and Rollback folders are empty, and SetupDiagResults.txt is also blank. CBS.log records 0x800703FA, but it does not include the failure details needed to identify the cause.

    Please manually copy the following into a new folder on your desktop, accepting any administrator permission prompts:

    C:\Windows\Logs\CBS — the entire folder, including CbsPersist files.

    C:\Windows\INF\setupapi.dev.log

    C:\$WINDOWS.~BT\Sources\Panther

    C:\$WINDOWS.~BT\Sources\Rollback

    You can paste these paths directly into File Explorer’s address bar. Compress the copied folder into a ZIP, check that it contains files, and share it through OneDrive. If copying fails, please share the exact message.

    Microsoft’s setup log locations: https://learn.microsoft.com/en-us/windows/deployment/upgrade/log-files

    These logs should help narrow down a repair that preserves your files and apps.

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