PhpMyAdmin solution:
-- Login to your phpmyadmin. -- To the left select the ClientExec Database created. -- Click the "user_customuserfields" table. -- Search for the userid 100 -- There will be a row with a value that starts with sha256: - Edit this row and delete the entire entry, example: sha256:1000:gvoyL9UXv+lUXbdp+0+2cmJ3GpIZD7w:kWuARQ6K4HWNaopY9eQry4Wqga5MSRD5 ( DELETE THIS ) -- From the tables populated on the left, select the "users" table. -- Click the browse tab at the top and then click Edit icon of Admin user with userid=100. -- Find the password field, enter the new password and select PASSWORD from the dropdown to the left of it and then save. -- Now go to the "user_customuserfields" table on the left again. -- Click browse tab at the top and find the row with userid 100 and customid 4 and then make sure it's set to his email address and then save it. -- If the administrator is different from ID 100, you would need to look in the 'users' table for getting the ID.
Mysql command line solution:
mysql user_database update user_customuserfields set value='' where id=126; update users set password=PASSWORD("yourpasswordhere") where id=100;
Source: https://www.clientexec.com/members/knowledge-base/troubleshooting~78/lost-administrator-password~121