If you get the following errors after installing Dovecot with MySQL support on FreeBSD 10:
Jul 24 10:17:28 ramrod dovecot: auth: Error: auth: environment corrupt; missing value for DOVECOT_ Jul 24 10:17:28 ramrod dovecot: auth: Fatal: unsetenv(RESTRICT_SETUID) failed: Bad address Jul 24 10:17:28 ramrod dovecot: master: Error: service(auth): command startup failed, throttling for 60 secs Jul 24 10:17:28 ramrod dovecot: imap-login: Disconnected: Auth process broken (disconnected before auth was ready, waited 30 secs): user=<>, rip=209.17.40.27, lip=206.125.173.30, TLS, session=<iWLbar9xXuLRESgb> Jul 24 10:17:28 ramrod dovecot: imap-login: Warning: Timeout leak: 0x1171cdb0 (auth-server-connection.c:397) Jul 24 10:17:38 ramrod dovecot: imap-login: Warning: Auth process not responding, delayed sending initial response (greeting): user=<>, rip=209.17.40.27, lip=206.125.173.30, TLS, session=<WbKjbL9xX+LRESgb> Jul 24 10:17:58 ramrod dovecot: imap-login: Error: Timeout waiting for handshake from auth server. my pid=90189, input bytes=0 Jul 24 10:17:58 ramrod dovecot: imap-login: Disconnected: Auth process broken (disconnected before auth was ready, waited 30 secs): user=<>, rip=209.17.40.27, lip=206.125.173.30, TLS, session=<WbKjbL9xX+LRESgb>
Try reinstalling the mysqlXX-client package from ports.