Hi @ripedro, i would first find out where the disk space is used. How large are these folders ?
C:\Users\Username\AppData\Local\Temp\McNeel\Rhino\V6
C:\Users\Username\AppData\Local\Temp\McNeel\RDK\Texture Cache
(UserName) should be your user name of course.
_
c.
In total, both folders takes 41MB.
Yesterday night, I have been working on the file, but without rendering VRscan materials (I am on learning process with all this new tools), I found out that I don’t like to use them, and slowly I have been removing them from the file. It might be just a coincidence in which no VRscan materials were present on the renders and the free space on disk has not change… but in this case I don’t know how to deep search to find out those space monsters 
which are haunting my hard drive 
…
Let me remind, that I have dig through all the basic folders of Rhino, temps backups and so on. What I could not find is where Vray , if it does make them, keep their virtual files…
Thank you all for your support 