[howarde]

UPDATE user LEFT JOIN bounce USING (email) 
   SET user.email = ''
   WHERE bounce.email <> '';

I just ran this on a test database and it does remove the bounce emails from the user table, and leave the field blank.

Thanks for the help.

Could cause problems leaving that field blank. Have you checked for any plugins for bouncing emails I am sure there are some around

I'll wait a few days to see if anyone has any real evidence of issues with blank emails in the DB.

Thanks.