Hello Jerome,
Step 1 was already been done (coming from the help file)
If it does not solve the issue, please edit the file libraries/joomla/filesystem/folder.php
Around line 93 AND 122, please replace:
return JError::raiseError(-1, JText::_('Copy failed'));
by
return JError::raiseError(-1, JText::_('Copy failed').' '.$sfid.' => '.$dfid);
I got this error message : -1 - An error has occurred.
Copy failed /home/thejarfa/public_html/tmp/hikashop/front/views/checkout/tmpl/address_select.php => /home/thejarfa/public_html/components/com_hikashop/views/checkout/tmpl/address_select.php
there is something different about this file "address_select.php"
it says it has no owner ... is that normal ???
see attached document