In the 'Get Windows 10' program go to the the hamburger menu in the top left corner.
Go to 'View Confirmation'
Then 'Cancel reservation'
and 'Cancel reservation' again to confirm.
(You can always reserve again later)
or just uninstall that update.KB3035583
This does not cancel your reservation so if you entered your email you'll still get emails ext.
I made a topic on removing the update to add to this:
https://forum.teksyndicate.com/t/removing-get-windows-10-notification/81358?u=cuboid
Isn't it "View Confirmation"? It is for me, otherwise I'm having a brainfart.
Sorry - fixed.
Is there any downside/disadvantage if I don't reserve it?
Good question!