Civil 3D 2019 Win 10. I have one set of 5 drawings. When opening multiple dwgs with Sheet Set Manager I get a fatal error every time. When opening individually thru Sheet Set or by selecting thru Windows Explorer they all open fine, every time. They have all been purged and audited extensively. There are no unreferenced dwgs, pdfs, etc. All Page setups are good. Very simple dwgs. I deleted the Sheet Set dst and ds$ and recreated from scratch. Same problem. These sheet were originally created with Plan Production tools. This is the only project with this problem.
