Midnight Commander shows strange characters

If mc shows strange characters (lines are not drawn, ...) then the shell variable
LANG is not set correctly.
You can change the LANG variable permanently to be en_US.ISO-8859-1 like

echo "export LANG=en_US.ISO-8859-1" | sudo tee -a /etc/bash.bashrc

or just for the mc :

echo "alias mc='export LANG=en_US; mc'" | sudo tee -a /etc/bash.bashrc

Both worked for me.