I have an HP PSC 1410 All-in-one multifunction printer and scanner and I found out this morning that the scanner is not recognized although the printer works fine. These types of HP "all-in-one" multifunction units are some of the most common types available today and in the past and I found it a bit surprising that it wasn't fully supported out-of-the-box when it is fully supported in Linux Mint 11.
Anyway, the solution is to install 'libsane-hpaio' via Synaptic and then reboot. Now the scanner portion works fine. Since this package is included in Linux Mint 11 by default shouldn't it be included in LMDE by default as well?