I receive Unauthorize error after "Connect to SharePoint" confirms that connection is successful and download starts

If you use MetaVis Architect (either full edition or Trial), the user that you use to connect to SharePoint should have at least Design privileges (Full Control will also work).

If you use MetaVis Classifier or Migrator products (check what it has in the application title bar) then the user that you use to connect to SharePoint should have at least Contribute privileges on the site you connect to (Anything better than Contribute like Design or Full Control will also work).

MetaVis Architect Trial Edition that you receive when you select "Try Now" on www.metavistech.com requires at least Design privileges because it includes Architect product.