Windows is no longer activated after changing system time

My machine has been running just fine for a couple of years, surviving an upgrade from Windows 7 and multiple Windows reinstallations without any problems concerning activation. I am not sure where I got the key from back in the days, but I am certain I bought it on the internet.

Some days ago, I changed the system date into the future and back again when testing some software. I used to do this in the past and never experienced any problems. This time, however, shortly afterwards, an open Microsoft Office reported that it had detected an error and needed to be closed. I uninstalled and reinstalled Office, which failed. Only then did I realize that apparently Windows itself wasn't activated any more.

In system settings on the Activation page, Windows shows the error 0xC004F012. Trying to troubleshoot activation in Windows shows me error 0xC00000, so apparently there is some sort of permission error invoking the activation routines. I also noticed that the Software Protection service cannot be started (Error 5: Access is denied.)

I carried out the steps described here. The results of the diagnosis are attached.

I also tried what was suggested here: I booted into Windows PE and ran DISM using an ESD file generated by the Media Creation Tool. As far as I could tell, neither sfc nor DISM could find any errors. After rebooting, the error persists.

Is there anything else I can try?

I am on Windows Version 1909 (Build 18363.778).

LicensingDiag.txt

I suggest you edit out that installed key on your screenshot
Posting it is an open invitation to anyone browsing the site to attempt its use.
Whatever your problem is, if Microsoft activation servers detect its multiple use attempts it will not help your case, unless you have the official receipt for the purchase of the retail edition

Yes sorry just realised that
As my colleague says, that is the Microsoft default key, for 10 Professional.

If the windows was activated against the key of a 7 or 8 Professional and has now lost its activation, as you say, OR if it was digitally activated by other means, then if you use the automated online service - you should have no problem.
(Perhaps I should add, if it was activated using a means that is STILL valid)

To do so you ensuring you are connected to the internet, you
type

run
in the search box on the taskbar
or you press the Win key + R

at the run cmd you type

slui 4

a window will open, basically you simply follow the instructions and if it was digitally activated, it will be again
When I have done it for others, personally and on a forum, I have always advised to have a pen and paper handy

NOTE the problem could have been caused by the date switch.

EDIT
I sort of knew that Brink - the admin of this site would have a tutorial on it - but I could not find it at first.
Activate Windows 10

Option 4 deals with my suggestion, but in the great detail of the Tutorials by Brink.

There is also mention of slmgr /ato - option 3 - you could try it, but I am not sure it will work in your case.
If it does it is far easier than going down the route I suggested.

Are you connected to the internet
If so and you open run and type
slui 4
it should open a blue screen with the first entry being select your country or region

If it does not what does show - anything or NOTHING
type that slui 4
with no windows open other than the desktop and of course immediately before the run window
You must be signed in as a user with admin rights

SUGGESTION - having read the errors received and the messages re the inability to open etc.
Download media creation tool
https://www.microsoft.com/en-gb/soft...load/windows10
think you said you already had

ISO to desktop
Mount
click setup
DO NOT BOOT FROM made USB etc
See this
windows repair install
Repair Install Windows 10 with an In-place Upgrade

PLEASE follow it carefully

I am signing off - goodnight
good luck with it.

@shrillcurse

See this post I Got Windows 10 For Free When You Could, Now it's Deactivated Itself

PS: you may want to read the entire thread - it's quite informative

To ensure you’re running a genuine license:
Right click on start & choose powershell with admin & enter: slmgr.vbs /dlv

Rebuild the tokens.dat file:
Navigate to “C:\Windows\System32\SPP\Store\2.0 directory” and look for “tokens.dat”. Rename this file to “tokens.old”. Now open CMD as an administrator and type in the following command and press enter after typing each command.
net start sppsvc
cscript.exe slmgr.vbs /rilc
After that, restart your PC twice. Then go to Settings, then Activation and run the Activation Troubleshooter.