Upgrade to 12.10 from 12.04 not available in update manager

My update manager does not give me the option to upgrade to Ubuntu 12.10. That is, the "New distribution release '12.10' is available. Click Upgrade and follow the on-screen instructions" section is not shown.

I had the same problem upgrading to 12.04. Spent hours trying to upgrade the system, got lucky somehow, don’t definitively know how.

What I have done,

• used Synaptic to clear package cache.


• reloaded package list and upgraded all packages.


• checked that ubuntu-standard and ubuntu-desktop packages are
  installed.


• checked that the "notify me of new version" setting in update-manager is set to "all new versions"


• update manager reports there are "no new updates"


• sudo do-release-upgrade -d reports no release available


• running update-manager -d does not help.


• cat /etc/lsb-release output is: DISTRIB_ID=Ubuntu DISTRIB_RELEASE=12.04 DISTRIB_CODENAME=precise DISTRIB_DESCRIPTION="Ubuntu 12.04.1 LTS

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Was able to upgrade my system by downloading the Ubuntu 12.10 desktop iso image, writing it to DVD and booting from it. The installation utility has an option to upgrade the current installation rather than reinstalling a complete new system.

I did not lose my home-folder data, however, I lost all other system configurations and had to reinstall all non-default apps. I suggest making backups before installing.