Some, but not all, of my pipe networks disappeared from profile views in AutoCAD Civil 3D 2013. The networks were still displaying in model space...I just had to re-add them to the profile views. Is this an issue that will be corrected from Service Pack 1?
If profile entities are on a layer that is locked when the drawing is closed, when it reopens it will not be able to draw the items in the profile view, skipping them. I remember redoing my profiles a few time before figuring this one out.