KDE do not works with custom locale

[Aragorn]

Well, then all I can do is point you toward this tutorial below.

[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. TL:DR As root edit the file /etc/locale.gen Enable the needed locales - including en_US.UTF-8 UTF-8 as fallback. 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 …

Beyond that, my hands are tied.