When I work on Wordpress development with Mamp (OSX), I sometimes have a problem : only Apache server wants start, even if I quit and relaunch. It's probably due to conflict with other programs and livereload stuff I use to.
I found an efficient solution in a forum.
Close Mamp and open your Terminal :
# 1 ps aux | grep mysql # 2 lsof -i # 3 killall -9 mysqld
Now open Mamp, start servers and it'll be ok.