Windows 10: Supressing Expiring Windows Insider Build Messages

My PC is running the Windows 10 Insider Build 21390.2025 Actually it's firmly stuck on that build after Microsoft about 18 months ago managed to do something wrong with the updates, and pushed my machine up to Windows 11 even though it didn't meet the specification and I had to downgrade it back to Windows 10, there were a few people with that issue that Microsoft threw under the bus which I won't be doing any beta work with their company ever again I have a valid Windows 10 licence key too, but changing the key didn't work.2 things have occurred pretty much at the same time, firstly a contr

:)

 

Windows insider build has expired....

Since you haven't reverted it back to public build before the expiration, I'm afraid you'll have to clean install as your system will automatically reboot every 3 hours or less.

https://answers.microsoft.com/en-us/insider/for...

 

Windows 10 insider build expiring.

Hi,

Yes. Insider builds before 18290 are expiring on 14/12/2018.

Switching rings mean you can expect the feature update in the next 48 hours. If still doesn't show up, let us know for further steps.

 

Windows 10 insider build expiring.

Couple of days ago, I received a message saying my build will expire on 14th of December, 2018. Now I'm an insider who was on the slow ring up untill yesterday when I switched to the fast ring hoping that I will get an update and the problem would fix itself.
Now, my question is what should I do???

When I type winver I see this:

Version 1809 ( OS Build 18272.1000)

* Some text about trademark and property *

Evaluation copy. Expires 14-Dec-18 6:29 PM

Also, in Settings -> Update&Security -> Activation, I have this:

Edition: Windows 10 Pro Insider Preview

Activation: Windows is activated with a digital license linked to your Microsoft account.

How can I fixt this? I'm prepared to do a clean install although I really don't want to because I got an SSD 3 weeks ago and I did a clean install then and the process of doing it again now is painful.

Is there a way to download the newest build from the "Check for updates" button or maybe download it from somewhere and install it manually? Will that fix the problem? I read articles from 3 years ago that installing newer build will fix it but that was
3 years ago. Also, how can my build expire when I'm an insider??