I made a transfer of users database from one site (Joomla 1.0) to another (Joomla 1.5). Due to encoding problems I made it manually, table by table (jos_users, jos_core_acl_aro, jos_comprofiler...). I tested this transfer several times until I have been happy with the results: new CB recognized old users, old users could easily log in, avatars were in place, profile hits, everything. But...

It turned out that old users could not edit their CB profiles. Any attempt to click "Save" results in error message "This email already exists" as if there is a new user registration, not editing of existing user (the site requires unique email for new user registration). At the same time all new users can edit their profiles without any problems.

I have reviewed records of new and old users in the database but have not found any particular differences. I have turned off front-end editing of emails in CB - no change...

May be I have not checked all the tables in the database or missed other thing in CB configuration?

Any thoughts?

SOLVED. Many old users had identical emails which was allowed in Joomla 1.0 but strictly forbidden in Joomla 1.5.