Fix Broken XREF Paths in 2018
Ron Couillard of USCAD demonstrates how to employ the new XREF Manager right click menu tools - Select New Path and Find and Replace to set new XREF paths in Civil 3D 2018.
From the USCADBuilding YouTube channel
and Ron Couilard's blog on USCAD.com
Priceless. A core 2018 AutoCAD new feature for XREF management that is too easy to forget... until you need it.