Buzzsaw is a 32 bit application
When uploading DWG Files to Buzzsaw external references will be resolved by the viewer i.e. DWG Trueview.
DWG Trueview will need to be installed as a 32 bit application.
Why?
Anytime we view files in Buzzsaw we view the file with the corresponding software application on PC that is associated with that file type. Since Buzzsaw is a web based application files on local PC need to have the ability to launch inside of Internet Explorer. You can test this by doing the following:
On your PC Right click on any filename, shortcut menu choose Open with and select Internet Explorer. If you can view file within Internet Explorer you will be able to view file in Buzzsaw.
64 bit files cannot open within 32 bit Internet Explorer. 32 bit Internet Explorer doesn't have a plug-in to read 64 bit files.