Levels save very slowly

Ok I have recently started a new project, it contains a couple of thousand trees and about 50K worth of grass meshes. This was never a problem for the editor in saving it to my drive, but a couple of days ago, something changed and it takes, between 3 to 8 minutes until it has saved the content to my drive. Before that it might have taken a minute tops.

Anyone have any idea what is going on here?