MAMP mysql server won't start. No mysql processes are running

What worked for me was removing all files (but not directories) in the mysql dir.

Edit #2 As per answers below, you only need to delete the log files: [ib_logfile0, ib_logfile1]

So quit MAMP and then in the terminal:

rm /Applications/MAMP/db/mysql/ib_logfile* #(or wherever your MAMP is installed)

Edit!: A few people have mentioned that you may want to back up these files first in case anything goes wrong, so maybe just use mv instead:

mv /Applications/MAMP/db/mysql/*  /tmp/.

If this doesn't work go back and kill all processes: sudo killall -9 mysqld

This is also duplicated here: mysql server won't start MAMP

The easiest solution: quit MAMP and remove the log files from MAMP/db/mysql directory [ib_logfile0, ib_logfile1] and restart MAMP. For more visit http://juanfra.me/2013/01/mysql-not-starting-mamp-fix/

rm /Applications/MAMP/db/mysql56/*

Works fine, but then it shows "No database found" in phpmyadmin although there are databases, so my drupal gave me errors because of this.

All I need to do is simply remove two files ib_logfile0 and ib_logfile1 from /Applications/MAMP/db/mysql56/ and that did the trick for me.