Share Email Facebook Twitter LinkedIn To Unload or Reload an Underlay Click Insert menu Reference Manager. In the Reference Manager pane, select a DGN underlay. Right-click, and click Unload or Reload. When unloaded, the DGN underlay is still linked to the drawing file, but it is not displayed in the drawing. Related Concepts About Unloading Underlay FilesAbout Underlays Related Tasks To Attach a PDF UnderlayTo Detach an Underlay