I have Autodesk Docs installed, and I can browse to the folder in Explorer and see the files (files are marked as synced). When I'm in Revit and I try to link in the Revit file I don't see anything (just empty folders).
its weirdly hidden in explorer in that window. but if you click the "my computer" icon in the link window it will show up as "Autodesk Docs" and you can browse to it from there.
