XDebug stopped working in PHPStorm

Don't you hate it when you spend hours wrestling with something, then in desperation try something simple, and it works?

I decided to try a different port, 9001 instead of the default 9000, and it WORKED!

I now realise that I recently installed Twonky (for video streaming to my TV), and when I checked the settings, there it was... port 9000.

Had the same issue this afternoon - found this question along with several other SO questions so I thought I'd post the solution that fixed it for me.

I was missing a mapping to the file system. Which is odd because I've seen PHPStorm prompt me when they've been missing previously.

Hopefully this helps someone in the future :)