Check Home Directory C:/Users/Lab. The Environment var.

I have now spent hours trying to find a solution for the problem with 
setting the environment variable Home. It is today pointing to 
C:/Users/Lab and C is an SSD disk! The warning notice pops up every time 
I start Eclipse. So WHERE do I set this variable? And where should it 
point to? A directory suitable for all files Eclipse saves, I suppose?
Probably a simple question for people who KNOWS???
Please help before my SSD crashes!
Nils