If you are using a USB authentication device, maybe for 2-factor-auth in the browser, and the USB key is not recognized by the system, this might help:

In the beginning I installed libu2f-host0, I am not sure if it is necessary:

sudo apt-get install libu2f-host0

It is necessary to have permissions to access the usb key. If there is not yet a rule in /etc/udev/rules.d you can create one like this:

cd /etc/udev/rules.d
sudo wget https://raw.githubusercontent.com/Yubico/libu2f-host/master/70-u2f.rules

The new file /etc/udev/rules.d/70-u2f.rules contains rules for the most frequent vendors and their models.

Now edit the file and replace

TAG+="uaccess"

with

GROUP="plugdev", MODE="0660"

The reason behind this, the rules file provided by Yubico assumes you have systemd running. See https://blog.flameeyes.eu/2014/10/setti … n-general/

I also restarted udev, don't know if it is necessary:

sudo service udev restart

The whole process was tested on devuan ascii.