Hi,
I'm not sure since I was never able to reproduce the problem.
However, let's try:
- extract the HikaShop install package on your local computer.
- edit the file back/helpers/database.php and change the line:
$query = 'UPDATE `#__hikashop_user` AS hku LEFT JOIN `#__users` AS ju ON hku.`user_email`=ju.`email` SET hku.`user_cms_id`=ju.`id` WHERE hku.`user_cms_id`!=ju.`id`';
to:
$query = 'UPDATE `#__hikashop_user` AS hku LEFT JOIN `#__users` AS ju ON (hku.`user_email`=ju.`email` COLLATE utf8mb4_general_ci) SET hku.`user_cms_id`=ju.`id` WHERE hku.`user_cms_id`!=ju.`id`';
- zip again all the files/folders in a new install zip
- install the modified zip
Let us know if it works of if you get an error.
If it works, we could include this change to avoid that error when there is a mix of collations (I suppose because of old Joomla table collations, or database setup).