Very old versions of MaxCut Community Edition required a monthly registration code to work. The latest version of MaxCut does NOT require a registration code.
If you are being prompted for a registration code you are running an extremely old version of MaxCut and we would recommend you upgrade.
We would also like to ask for your help. We are trying to identify sites that are still providing copies of our old MaxCut installer. If you know of a site that is still providing the old installer of MaxCut please email us with the site address so that we can notify them of the latest download - it helps future users.