I'm new to Linux Mint 12 and I can't tell for sure, but I think I'm missing some updates. When I run update manager and it's fetching the list of packages to be updated, a bunch of packages list status: failed.
And when I run sudo apt-get update, a couple packages say Hit but most are listed as Ign (which I assume stands for Ignored).
I know that Mint purposely avoids installing some updates because they're not yet considered stable, but this looks like it's not even fetching the list of available updates.
Specifically I added the repository http://ppa.launchpad.net/jamesodhunt/bug-829980/ubuntu for a particular bug-fix which didn't seem to work, I think because the repository is being ignored.
I can't seem to find any references anywhere to other people having the same problem. Everything I've found where people are having trouble fetching packages for updates, they seem to be getting explicit error messages, but I don't see any.