[root tip] [How To] Troubleshooting locale errors

Difficulty: ★☆☆☆☆

Locale Errors

Locale errors are not always obvious and some applications simply stop working without any hints at all - e.g. Gnome Terminal is very sensitive to incorrect configuration of locale.


  1. As root edit the file /etc/locale.gen
  2. Enable the needed locales - including en_US.UTF-8 UTF-8 as fallback.
  3. Rebuild the locale database using the locale-gen script

Calamares installer

The Calamares installer adds the locales chosen to the end of /etc/locale.gen so check the last lines of the file before editing - it looks something like this

# Locales enabled by Calamares
en_US.UTF-8 UTF-8
en_DK.UTF-8 UTF-8
da_DK.UTF-8 UTF-8

General locale configuration

From time to time an update may install locale.gen as locale.gen.pacnew - do not blindly overwrite your existing locale.gen. Before applying the new file - check the locales in use and reapply the configuration after applying the .pacnew file.

If you have been modifying locale and are having locale trouble ( KDE/Plasma :eyes: ) it can be difficult to locate the offending setting because scripts and rc configurations can change locale outside the obvious locations.

The first place to look when dealing with KDE/Plasma is usually ~/.config/plasma-localerc.

Locale error message

From my notepad

When you get errors like these examples - it is not obvious what causes it

$ rofi

(process:1628): Rofi-WARNING **: 07:34:43.942: Failed to set locale.
$ sterminal
couldn't read from shell: Input/output error
child exited with status 1
tmux: invalid LC_ALL, LC_CTYPE or LANG

Check your settings

:information_source: Obviously you need to replace the locale with something relevant for your system. I have written this using my system’s locale - en_DK for messages and da_DK for the rest of the system.

Check locale settings

$ localectl      
   System Locale: LANG=en_DK.UTF-8
       VC Keymap: dk-latin1
      X11 Layout: dk
       X11 Model: pc105

Check installed locales

$ locale -a

The installed locales does not match the settings listed by localectl - as you can see the da_DK part is missing.

Fix locale error

It is recommended to use the utf8 version unless you have compelling reasons to select otherwise.

Method 1

Edit /etc/locale.gen and ensure that all in-use locales has been uncommented. For fallback messages enable en_US as well

$ sudo nano /etc/locale.gen
#cy_GB ISO-8859-14  
da_DK.UTF-8 UTF-8  
#da_DK ISO-8859-1  
#en_CA ISO-8859-1  
en_DK.UTF-8 UTF-8  
#en_DK ISO-8859-1  
#en_SG ISO-8859-1  
en_US.UTF-8 UTF-8  
#en_US ISO-8859-1  

Method 2

Based on the comment by @nam1962 (see below).

Check if the locale you want to use is available in the locale list (/etc/locale.gen)

$ cat /etc/locale.gen | grep 'da_DK'
#da_DK.UTF-8 UTF-8  
#da_DK ISO-8859-1

Use sed command

  • To enable a locale (uncommenting the line)

    $ sudo sed -i '/en_DK.UTF-8/s/^#//g' /etc/locale.gen
    $ sudo sed -i '/en_US.UTF-8/s/^#//g' /etc/locale.gen
  • To disable a locale (aka commenting the locale)

    $ sudo sed -i '/en_DK.UTF-8/s/^/#/g' /etc/locale.gen

Rebuild locales

$ sudo locale-gen
Generating locales...
  da_DK.UTF-8... done
  en_DK.UTF-8... done
  en_US.UTF-8... done
Generation complete.

Recheck your locales

$ locale -a      

Verify it works

➜  ~ rofi -r
Rofi is unsure what to show.
Please specify the mode you want to show.

    rofi -show {mode}

The following modi are enabled:
 * window
 * run
 * ssh

The following can be enabled:
 * windowcd
 * drun
 * combi
 * keys

To activate a mode, add it to the list of modi in the modi setting.

Moved to #contributions:Tutorials so it appears at the top instead of all the way at the bottom of #contributions


I have french user I installed, they don’t even know nano exists.

Thus I told them :

sudo sed -i '/en_US.UTF-8/s/^#//g' /etc/locale.gen
sudo sed -i '/fr_FR.UTF-8/s/^#//g' /etc/locale.gen
sudo locale-gen

For other languages, just replace fr_FR with the proper locale

[Edit] to reverse & comment out :
sed -i '/fr_FR.UTF-8/s/^/#/g' /etc/locale.gen
with the proper locale :wink:


Nice idea - I will add it to the guide :slight_smile: thank you.

1 Like

Thank you for praising :wink:

By the way, my checking outcome is a little different :

[meuh@ordi1 ~]$ localectl
   System Locale: LANG=fr_FR.UTF-8
   VC Keymap: fr
  X11 Layout: fr
   X11 Model: pc105
[meuh@ordi1 ~]$ locale -a
[meuh@ordi1 ~]$
1 Like

2 posts were merged into an existing topic: Manjaro Settings Manager - Locale settings - Language