The machine initially had a current intrepid on it. I started the upgrade to jaunty (update-manager -d), and killed the virtual machine while it was installing packages. After rebooting the VM and logging in, the update-notifier informed me the system was broken and needed fixing and gave me instructions on how to start synaptic. So far so good.
Then I went back to the pristine, up-to-date intrepid VM (the joys of virtual machines), and re-started the upgrade to jaunty. This time I killed the upgrade in the middle of downloading the packages. After rebooting the VM and re-starting the interrupted upgrade, it continued downloading from where it had gotten when I killed the VM.
I used a virtual machine to test this.
The machine initially had a current intrepid on it. I started the upgrade to jaunty (update-manager -d), and killed the virtual machine while it was installing packages. After rebooting the VM and logging in, the update-notifier informed me the system was broken and needed fixing and gave me instructions on how to start synaptic. So far so good.
Then I went back to the pristine, up-to-date intrepid VM (the joys of virtual machines), and re-started the upgrade to jaunty. This time I killed the upgrade in the middle of downloading the packages. After rebooting the VM and re-starting the interrupted upgrade, it continued downloading from where it had gotten when I killed the VM.
Thus, I think the bug is fixed.