For several months, by Ubuntu server has complained every time I do an apt-get upgrade, with the following message:
dpkg: serious warning: files list file for package `[package name]' missing, assuming package has no files currently installed
There were easily a hundred packages that listed this way, and I couldn't figure out how to resolve it. Today, I ran across this post on the Ubuntu forums, which suggested the following command:
sudo dpkg --clear-avail
That seemed to do the trick...updates go smoothly now! Apparently, I broke the available packages list somewhere along the way...