Get halfway through a model and find it's an unworkable mess? Can't add edge loops where you need them? Can't subdivide a mesh properly? If any of this sounds familiar check this course out.
I was working on a CPS face, I saved the file and when I reopened the file the geometry had gone. This was the same with all 4-progress saves. If I have to restart then I will, I’ll get more practice, but I am wondering why it happens.