Thanks for that Dean.

Just so I understand: I have the very latest updates for my AutoCAD 2017 software / OS X and yet I cannot open this file?

I have checked the Autodesk web-site and they do not appear to market AutoCAD 2018 for Mac's?

If this is the case then it is extremely poor service and I now have to undergo the embarrassment of asking the file creator to down grade the DWG!!

Come on Autodesk give Mac users a chance ...... there is a big OS X market out there!!

.