Movies that I cannot find are taking up 200 GB on Mac
The How can I figure out what&#39;s slowly eating my HD space? provides a general approach to answering your question.

Graph and Find

You can use a tool like GrandPerspective to help highlight large files on your Mac:



Disk Inventory X is an alternative disk space visualizer:



Ask VideoBlend's Developers

Consider contacting the makers of VideoBlend, via videoblendteam@gmail.com, and asking them directly. This may help prompt the developers to improve their caching approach in the future.