After the distro upgrade from Ubuntu Karmic to Lucid my fingerprint scanner apparently stopped working. As it turned out, this problem is not that uncommon (cf. https://bugs.launchpad.net/ubuntu/+source/thinkfinger). In fact, the scanner was working but required pressing the Enter key after each scan for the authentication to work. Unfortunately, this is not the way it’s supposed to work and not very comfortable either, as the scanner solely serves the purpose of comfort.
The best solution for the time being is to install the thinkfinger package from Martin Schwenke’s PPA. (see https://launchpad.net/~martin-meltin/+archive/ppa)
In order to do so I executed the following in my bash:
sudo add-apt-repository ppa:martin-meltin/ppa
sudo apt-get update
sudo apt-get upgrade
After that the scanner worked as expected. Big thanks to Martin!