I created a 1 m buffer around a bunch of complex polylines. I then deleted the sections I didn't want based on Area. I then tried using the new buffer polygon to clip the polylines. The clip tool ended up deleting most of the lines that existed within the polygon(s). I've tried about everything (using the intersection tool, used the select by location and save it out as a new polygon (gave an error), tried using the erase tool (which failed)) and am about out of ideas or reasons why it would do this. I even used the repair geometry tool to make sure that was not causing a problem. The only thing I could think may be happening is that it is too large/complex so it is only completing part of the clipping process. Below are a couple of pictures. The first is showing all of the polylines (in red) and what the clip output is giving (in green). the second figure is showing that the buffer polygon is in fact enclosing both the output (green) and what was left out as part of the output (again in red). If anyone has any ideas as to what is happening I would very much appreciate any help I can get.