SymptomsCreate a copy of the existing database at Websites & Domains > Databases > DatabaseXX > Make a Copy > Create database with name DatabaseYY. The newly created database does not contain any tables which are supposed to be copied.
ResolutionPut DbCloneHelper.php file from the archive attached to the present article to %plesk_dir%\admin\plib\api-common\DbCloneHelper.php
Add a database user in the Parallels Plesk Panel interface to be able to manage the newly created database via the database Webadmin.
This problem has been fixed in Parallels Panel 10.4. Consider upgrade Parallels Panel on your server.