How to force Plesk admin user to change his password on first login?
This feature is not available in Plesk 12.5. Currently it is under review, you can track its status on Plesk uservoice portal.
Plesk 12 or earlier:
# mysqldump -uadmin -p`cat /etc/psa/.psa.shadow` psa > psa_dump.sql
Login to Plesk database:
# mysql -uadmin -p`cat /etc/psa/.psa.shadow` psa
Run the following query to force password change:
mysql> update misc set val='false' where param='psa_configured';