Note: This article has the reference to the issue with the fix available:
"If MySQL server data directory in Plesk for Windows was changed so that it differed from the location of MySQL server executable files, WordPress could not be installed."
- WordPress Toolkit 2.0 23 March 2017 (Windows)
Unable to install WordPress with the following error:
'mysql' is not recognized as an internal or external command, operable program or batch file.
MySQL is installed in non-standard location. For example:
MYSQL_VAR_D- C:\Program Files (x86)\Plesk\MySQL\
WordPress ToolKit bug with id #EXTWPTOOLK-326 . The fix is considered to be included in further Plesk updates.
Replace the %plesk_dir%\admin\plib\modules\wp-toolkit\library\Capability\Windows.php file with attached one.