I have done some more checks and I have narrowed it down to my host PC. From my viewer I can connect to another host and download files with ease. I do not think the issue is directly related to dwg files as I am having difficulty with all file transfers.
Both systems are up to date running the same version. I have fully uninstalled both viewer and host along with removing legacy registry. and carried out a clean install. I have uninstalled third party anti-virus from host and added exception to windows defender. When Transferring files the status bar often gets stuck at 2mb intervals. Sometimes pdfs and smaller files transfer ok but large files in excess of 2mb often transfer corrupted or incomplete.
Both versions are the same. This only started to happen this week, I have noticed that the utility is slow also, pdfs transfer fine but slowly and .dwg transfer but will not open so may not be completing transfer or becoming corrupt. I am working from home today so I do not have perfect access to me host computer.
When I am back in the office I will try an uninstall and re-install using the only guide.
Until recently everything was working great. However now when I transfer or copy a .dwg (autocad drawing) the file isn't correctly transferred, when I try to open the file autodesk reports that the "drawing file is not valid". I can still copy other files like pdfs.