Above "error" is likely because EoL of a Feature Version. https://docs.microsoft.com/...dows-10-home-and-pro
Sound like has already DL a newer/newest version, maybe partly installed now and will completely install next reboot.
At this point you have little to no choice to get the upgrade.
You may be able to rewind the upgrade but don't count on it. Worse, That can "brick" a machine too.So Backup your Data Before you reboot for any reason.
MS Updates and Upgrades has Decades of History "breaking" machines and can't boot.
Not just Desktops etc used by normal users but crashing Servers, breaking Exchange, MS SQL, and others often Costing Thousands to Millions of $ Per Minute of Down Time.
(External HDD on USB3 runs almost as fast as internal HDD and bigger and cheap. I use several 1TB External HDD for just this reason.)
As to Blocking updates and upgrade in the future...
Win10 Home have very limited ways to avoid updates/upgrades. Also GPedit does not apply here. Can try RegEdit but doesn't always help or make more problems.
Win10 Pro w/o AD for SOHO use have a little more ways to avoid but will try to force an update/upgrade too.
Win10 Pro w/ AD and Win10 Enterprise has many more ways but MS force upgrades there too in the end.
(Active Directory connection in a Enterprise setting. I believe MS change names but still is AD to most Net Admins.)
I have Win10 and Win7 as dual boot on main machine and still use Win7 for 99+% of time.
I have tried Win10 on "old" machines (For MS "Old" is anything > 3 to 5 years.) but MS has block more and more drivers to run it. Even most drivers to run on x64 Win7 and 8.x won't run or install on many Recent x64 Win10 versions.
Example: One laptop I have can't use BT when Win10 is used because no new Win10 drivers for builtin BT "card." Did run on older Win10 but not now.
For future use...
From MS itself, Is or Was
a way to DL newer version to DVD/flash then install but more complicated. Plus often have to DL days to months before now from MS to get more recent version but still avoid the newest.
You dig thru MS Win10 site to find a tool to DL offline image to DVD/flash then install. Should be @ https://www.microsoft.com/e...e-download/windows10
but haven't tried recently.
Install may have extra steps to avoid having MS Accounts because now trying to force everyone to have them during OS setup/install not just access to MS App store. (I think just install w/o Net connection to the machine.)
If you take this option... DL x86 and x64 so one DVD/Flash "disk" carries all versions. DL at night because will eat ~ 8GB and often DL faster from MS. If your on a Capped Data plan then try to find a friend w/o a cap.
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