Modern versions of Mac OS X include a built-in batch file renaming tool that allows Mac users to instantly rename large groups of files, folders, photos, or anything else residing on their file system in a single action. Doing that by hand, especially to dozens of files and folders, is slow going, and Mac OS X hasn’t provided a way for us to batch rename files natively. That’s okay, because we can still get the job done. Advanced Renamer is a program for renaming multiple files and folders at once. By configuring renaming methods the names can be manipulated in various ways. It is easy to set up a batch job using multiple methods on a large amount of files. Rename X 1.0.2 - Hassle-free file renaming application. Download the latest versions of the best Mac apps at safe and trusted MacUpdate Download, install, or update Rename X for Mac from MacUpdate.
It's called Filebot. I was having lots of problems with 'The Renamer' and 'TV Rename' but FILEBOT gets it done in the easiest to use interface I have found.
I just had to share as I've been struggling with plex not finding my shows for a while.
[Download From Source Forge] (http://sourceforge.net/projects/filebot/files/filebot/HEAD/FileBot-setup.exe/download)
And the dudes actual website here
Renaming Mac Computer
Edit: I am in no way affiliated with this project, but I had to share to solution to many of my plex frustrations with everyone else here.