In the System settings -> Account details I've changed 2 fields "Name and Surname" and "Password". After rebooting I couldn't log in to the system. I could access my user account with the new password via terminal, but via windows after entering the new password the log in page disappeared for a second and appear again with the request to enter the user password, again. The log in page has working in a loop. I have basic mint KDE 18 installation, but I encrypted my home folder during the first installation. To solve the issue I had to reverted my user password to the previous one. Then I could log in to my system again.
*** This bug has been marked as a duplicate of bug 364365 ***