So this happened the other day. I was organizing some Plex Media into folders like A-M and N-Z. After doing that, I noticed that almost half of my cache drive was used up. I'm guessing this is in relation to the move. Can I recoup that space? 

Ok.. wait after restarting the server it has retuned to normal levels. I guess I'm more trying to understand what happened?

I would guess that your reorganization had Plex create new files. But this happened faster than Plex cleaned up the files in the old location.

Makes sense.  Just wanted to be prepared for any future moves. Thanks!