I've got the Illegal mix of collations error after upgrading from 4.1 to 5.0.6.
It only shows up when I look at Dashboard > Emails > Addresses so it's not critical. But nobody likes to see that red error text.

I followed the advice here http://stackoverflow.com/questions/1008287/illegal-mix-of-collations-mysql-error?rq=1 and then went through every single table and column in the database and made them all utf8_general_ci. They were not all the same at first.

But the problem persists. Error as follows:

MySQL error!

Illegal mix of collations (utf8_unicode_ci,IMPLICIT) and (utf8_general_ci,IMPLICIT) for operation '='(Errno=1267)

Your query: Results::Query()

SELECT SQL_NO_CACHE emblk_ID, emblk_address, emblk_status, emblk_last_sent_ts, emblk_sent_count, emblk_sent_last_returnerror, emblk_last_error_ts, 

( emblk_prmerror_count + emblk_tmperror_count + emblk_spamerror_count + emblk_othererror_count ) AS emblk_all_count,

emblk_prmerror_count, emblk_tmperror_count, emblk_spamerror_count, emblk_othererror_count, 

COUNT( user_ID ) AS users_count

  FROM evo_email__blocked

  LEFT JOIN evo_users ON user_email = emblk_address

 WHERE (emblk_status IN ('warning','suspicious3'))

 GROUP BY emblk_ID

 ORDER BY emblk_last_sent_ts DESC

 LIMIT 0, 20