WooCommerce 2.1 update ignores language preference
This issue is now resolved in the WooCommerce 2.1.1 fix release.
We’ve made an error when adding the language files. The country codes didn’t reflect the WordPress standards. We have now fixed this and the 2.1.1 patch release will contain the correct language code.
You can apply a temporary hotfix by renaming the language files for your language, inside the WooCommerce core plugin. It should reflect the correct code as shown in the standards. If you are on the Spanish language for example, you need to rename the ‘woocommerce-admin-es.mo’ and ‘woocommerce-es.mo’ files to include the ‘ES_es’ country code. The correct file names are ‘woocommerce-admin-es_ES.mo’ and ‘woocommerce-es_ES.mo’. These files can be found in the ‘i18n/languages’ folder of the WooCommerce plugin.
Ticket reference: #4708