Windows 11, version 25H2 for x64-based Systems (KB5070773) (26200.6901) Install error - 0x80070306

Tanner Baku 20 Reputation points
2025-10-20T22:13:14.6666667+00:00

I continue to get install error after about 27% installed listed in the title. I have run the Windows update troubleshooter in the settings and get the following response: I'm sorry.  I was unable to run the Windows Update diagnostic. I might need to transfer you to an agent to help solve your problem. Which has led me here... Any help would be appreciated. Thanks

Windows for home | Windows 11 | Windows update
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  1. Bob Badgley 10 Reputation points
    2025-10-22T12:31:17.8466667+00:00

    No I do NOT have a 3rd party anti virus.While I appreciate your time,this is a typical by the book MS answer,which on its own will not help anyone whatsoever.

    CK do you like copying and pasting the same response,because I don't like getting old and used clothing.If you'd really bothered to read my initial response you'd know I had to go in and reinstall Windows(without losing my files) to correct the original install of the 25H2 version.As an aside,I loved the 24H2 version because it virtually had NO bugs like this.So if MS can do that for the 24H version why can it not be that consistent with the 25H version?

    So here is what I finally did.I went back and did that reinstall of Windows without losing my files and it installed a 25H2 "repair" version onto my system which has fixed the problem...at least today.

    And to those reading this,here is the way to do that:(you see,unlike MS,I believe in getting to the heart of the problem instead is BSing peeps around to make themselves sound important):

    Go to System,to Recovery,to Fix problems using Windows Update.You tell it you want to keep your files and stuff and away you go.It will ask if you want to check a box to restart in 15 minutes(dealers choice-I didn't).Once done and installs, there may or may not be several restarts but it's all part of the process.Once done you're good to go.

    1 person found this answer helpful.

  2. CrazyKats 11,885 Reputation points Volunteer Moderator
    2025-10-20T22:28:39.8366667+00:00

    Hi,

    Do you have any 3rd party AntiVirus?

    If you do please uninstall it.

    Have you had this error previously?


  3. Bob Badgley 10 Reputation points
    2025-10-25T10:52:09.8266667+00:00

    AL I feel you're BSing me here.What I explained as the solution has nothing to do with registry keys,CSP or anything else.This is a built in procedure in Win/11 so one doesn't have to go into areas most don't understand.If you're going into other areas other than that I described its no wonder it didn't work.

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