Defects in Civil 3D (Civil 3D performance)
https://knowledge.autodesk.com/support/autocad/troubleshooting/caas/simplecontent/content/autodesk-autocad-civil-3d-performance-degradation-fix.html.
https://knowledge.autodesk.com/support/autocad/troubleshooting/caas/simplecontent/content/autodesk-autocad-civil-3d-performance-degradation-fix.html.