This guide covers typical errors that arise during (or after) the installation process and suggests the most probable solutions.
Problem: Vim produces errors which are clearly related to the encoding being something other than Unicode.
For example, the YCM plugin spits out something like the following line:
YouCompleteMe unavailable: requires UTF-8 encoding. Put the line 'set encoding=utf-8' in your vimrc.
However, even with set encoding=utf-8 the errors persist.
Reason: enabling Unicode at the Vim level is not enough. There may be some mess with encodings at the terminal level and so on, making Vim misbehave.
Solution: it is better to use Unicode system-wide. This is typically done
by setting the LANG variable to the appropriate value at the topmost level,
e.g. in systemd-based systems you may define it in the /etc/locale.conf
file:
$ cat /etc/locale.conf
LANG=en_US.UTF-8