PhpStorm debugger not stopping at BreakPoints; keeps waiting for xdebug _SESSION_

Try changing the xdebug listen port in your php.ini and your IDE.

Running Mac Yosemite, for me the problem was that I installed with homebrew, following a guide that used php-fpm, which uses port 9000 by default (which conflicts with the xdebug default port)... Changing my xdebug.remote_port to 9001 and changing the xdebug port in phpstorm fixed the problem, though I suspect this issue could happen for anyone in any IDE. I googled for the better part of a day and didn't see this solution (since I believe it's so specific to install method).. but I hope it helps someone.

These lines are crucial to make it work (in php.ini):

zend_extension=/usr/lib/php/extensions/no-debug-non-zts-20121212/xdebug.so
xdebug.remote_autostart = 1 # <-------- THIS
xdebug.remote_enable = 1 # <----------- AND THIS

Without these lines xdebug will never work on phpstorm ;)

Took me about an hour until I noticed that this button wasn't activated ;)

"Run" -> "Start Listening for PHP Debug Connections"