When I open the files from the start history (and it's in-use), it does not notify you the file is already open and ask if you want to open read-only. If you use the "open" dialog it will prompt you that the file is in-use and if you want to open it read-only. I am assuming this is not a setting and an issue.
This is a similar thread:
https://forums.autodesk.com/t5/civil-3d-forum/read-only-warning/m-p/9620596
Bruce Klug, P.E.
AutoCAD Expert Elite Alumni
AutoCAD Civil 3D Certified Professional
Civil 3D 2026
Win 11 Enterprise, 64-bit
