Users not being imported

If you edit the plugin and change line 17 so that IMPORT_DEBUG is true then you will get some more information as to why these users are not being imported.

define( 'IMPORT_DEBUG', false );

The most likely reason is that there are already users with the same login or email address registered to the site.

have answser this queston on another thread:
https://www.ads-software.com/support/topic/plugin-wordpress-importer-wordpress-importer-problem-all-posts-author-become-admin?replies=9

solution is remove non-word char(non alphanumeric character and the underscore),
that is makesure usename only contains alphanumeric character and the underscore.

or goto my post to find detail info:
【已解决】使用wordpress importer导入WXR时出错：Failed to create new user for XXX. asign to the current user
https://www.crifan.com/2012/03/26/wordpress_importer_failed_to_create_new_user_for_asign_to_the_current_user/