Dear Marcin,
Have you tried to purge all caches? You can easily do this as the site admin by going to Site Administration > Development > Purge all caches.
Moodle can cache themes, language strings, filters and other bits of information that have been calculated and stored by the web browser. This link forces all user web browsers to refresh their screens of any information that Moodle has cached. Several modules that use cache have settings which will turn off caching for that module. Eliminating or purging caches slows performance. For more information, check out Purge all caches: https://docs.moodle.org/en/Developer_tools#Purge_all_caches
You might also want to double check that all the fields in the CSV are valid. You can find more information here: https://docs.moodle.org/en/Upload_users#User_Fields_that_can_be_included
I hope that this helps and you are able to update.
Kelly
Have you tried to purge all caches? You can easily do this as the site admin by going to Site Administration > Development > Purge all caches.
Moodle can cache themes, language strings, filters and other bits of information that have been calculated and stored by the web browser. This link forces all user web browsers to refresh their screens of any information that Moodle has cached. Several modules that use cache have settings which will turn off caching for that module. Eliminating or purging caches slows performance. For more information, check out Purge all caches: https://docs.moodle.org/en/Developer_tools#Purge_all_caches
You might also want to double check that all the fields in the CSV are valid. You can find more information here: https://docs.moodle.org/en/Upload_users#User_Fields_that_can_be_included
I hope that this helps and you are able to update.
Kelly