I was trying to edit polylines (waterlines) using AutoCAD Map 3D and after editing a few polylines some of the features I have edited are corrupt and do not show up when I add the shapefile to ArcMap.

I am trying to edit waterline locations because we now have valve locations and the waterlines need to pass through the valves. When i had to edit a feature, I checked it out, added a vertex or split the polyline then checked it back in. What did I do wrong?

What is the proper workflow so I don't hose my shapefile?