User sync issue

We are using Community Builder registration feature for a user registration. It will copy all the user data from jos_comprofiler table to jos_users table in database.

In Community Builder menu we can see Tools menu item; under it we have buttons ’Synchronize Users’ and ’Check Users Database’.

Pressing ’Synchronize Users’ will give an error message: SQL error Subquery returns more than 1 row . I check it few weeks ago and it worked fine.

Pressing ’Check Users Database’ infroms that everything is fine.

Checking Users Database:
All Community Builder comprofiler table rows have links to user table.
All users table rows have links to comprofiler table.
users table has no zero id row.
comprofiler table has no zero id row.
All rows in comprofiler table have user_id columns identical to id columns.
All users table rows have ACL entries in user_usergroup_map table.
All ACL user_usergroup_map table rows have corresponding entries in users table.

Question:
- Do you have any idea where to check the user sync problem in jos_comprofiler or jos_users tables?

Can't see how the sync query could throw "SQL error Subquery returns more than 1 row ". Review your _comprofiler table and ensure every row has the same value for id and user_id columns and ensure there's no duplicates (shouldn't be possible). If issue persists ensure Joomlas database is up to date by running Joomlas database tool within Extensions > Manage > Database.