I was upgrading from 11.10 to 12.04 and the process got stuck when reconfiguring/downloading dropbox. I had to break the upgrade at 87% and don't think my system will boot now. Is there any way to resume the upgrade in order to complete it?
I don't believe resuming will work. You will need to restart the configuration of all the packages.
During the Grub menu, after you start the PC, select (recovery mode). Then a menu will appear, one of them is about "dpkg" select it and reconfigure all the packages.
If the menu didn't appear, and you went into console mode you can run this command:
dpkg-reconfigure -a
If if was broken - as it was in my case -, and neither the menu nor the console worked. Then in the Grub choose a "Previous Linux Version" and select any of the Linux Kernel version in (recovery mode). I'd suggest the newest version. And follow the previous two steps.
(Well to be honest I think you can "resume" the upgrade, if you somehow managed to keep track of all the packages that weren't yet configured, by running dpkg-reconfigure package_name)
