About model and data exchange with 3rd party solutions: Revit, Solibri, dRofus, Bluebeam, structural analysis solutions, and IFC, BCF and DXF/DWG-based exchange, etc.
Yes, I know about the publisher, but sometimes just to make things faster i use the save as.
Anyway I don't know what was wrong, but I removed the addon, and replaced it with one used on another computer and it works fine now..
The computer had probably crashed during a dwg conversion and it messed it up.