Why does upgrade from 12.04 to 12.10 using a CD/DVD still require download?
Solution 1:
It's bad news, I'm afraid. Canonical removed the ability to upgrade using CD/DVD images from the 12.10 release.
All of the instructions I have seen for upgrading to 12.10 only talk about a network installation, usually using the Update Manager. See the 12.10 release notes. It is also mentioned in the 12.10 Beta2 Technical Overview, and there are lots of comments and complaints out there on the net.