I updated my Cubase 6 Elements to Cubase 8 Elements.
When I open Cubase 8 I get asked to enter an activation code.
But when I enter my activation code I get the notification that it was already used and can only be used once.
How to solve this?
Are you trying to enter the activation code that came with Cubase 6 again?
You need a new upgrade activation code that you should have been shown online during the purchase process and it should also have been emailed to you after purchase.