Windows 10: 20h2 results in missing operating system - any fix known?

Lenovo m90p, installation of 20h2 update to windows 10 consistently corrupts the C: partition of the disk and results in system refusing to boot with "Missing operating system".


Many hours wasted already - tried pretty much everything I could find, to no avail.


Anyone know of a fix other than reinstalling and consequently wasting yet more hours?

:)

 

Installing KB4592438, KB4586853 results in "Missing operating system"

He won't be able to do an in-place repair because of the bug in early releases of 20H2 that prevents it. That's part of the reason @jaap Verhage is trying to install the KB updates, to repair the bug.

Here is an apparent registry fix that will also fix the bug:
Repair Install Windows 10 with an In-place Upgrade

Then I would suggest getting the latest build of Windows 10 available from "TechBench" which is 19042.631 and doing the in-place upgrade repair with that:
TechBench by WZT (v4.1.1)





That should get things going on the right track again.

 

Programs not working

In post 26 there were steps listed to fix the operating system corruption.
Are you able to follow them?
In post 29 was the suggested dism repair command.

 

After updates Windows 10 says "Missing operating system"

I have the same issue, and I followed your suggestion steps. After that, I can see C: drive, and Windows folder is there.

Then I rebooted the computer. But I still have the missing the operation system issue. Any suggestions?

Thanks.