What is Eating Up The Internal Storage On My Z10?

I have checked all folders, all installed apps and games, and I am still somehow always maxed out around 15GB of 16GB. Is Box or Dropbox responsible? I have moved all photos and videos to the Micro SD card. I have only two games over 600mb on internal storage. Just cannot figure it out. Driving me nuts!

I used my Z10 to create this CrackBerry madness!