WordPress 4.2 adds utf8mb4 collation to MYSQL servers that support it when it runs update.php. It's very likely that your development machine is running the latest MYSQL version and you'll need to revert back to the DB collation that you had before 4.2 to support older verisons of MYSQL when doing a database migration. If you have WordPress inst…

utf8mb4_to_utf8

#!/bin/bash

DB_NAME="wordpress_test"
DB_USER_NAME="external"
DB_PASSWORD="external"
DB_HOST="vvv.dev"
DB_PORT="3306"

(
echo "ALTER DATABASE ${DB_NAME} CHARACTER SET utf8 COLLATE utf8_general_ci;"
mysql --user=$DB_USER_NAME \
      --password=$DB_PASSWORD \
      --host=$DB_HOST \
      --port=$DB_PORT \
      --batch \
      --skip-column-names \
      -e "SHOW TABLES" \
      --database=$DB_NAME |
xargs -I%TABLE_NAME% \
      echo "ALTER TABLE %TABLE_NAME% CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;"
) |
mysql --user=$DB_USER_NAME \
      --password=$DB_PASSWORD \
      --host=$DB_HOST \
      --port=$DB_PORT \
      --database=$DB_NAME

just download the Gist, make the file executable using chmod ug+x ./utf8mb4_to_utf8, update the variables on lines 3-7, and run the script in the terminal ./utf8mb4_to_utf8.