On Windows 10 and 11 (not tested on older versions) Picard logs an "unsupported locale settings" error when starting with a specific language configured.

The issue is that it tries to set the locale with encoding using locale.getpreferredencoding().

But this the encoding returned here might actually not be valid for the locale. E.g. on my systems it returns "cp1252". But locale.setlocale('de_DE.cp1252') fails. Only locale.setlocale('de_DE.UTF-8') or locale.setlocale('de_DE') would work (the latter without encoding would fail on Linux and likely macOS).

One issue this failure in setting the locale causes is that sorting does not work as expected, see PICARD-2386