Thanks for the response, and the suggestions! Although the Microsoft thread did not help, it did give me some ideas on things to try. I figured it out, so I'll note here in case it helps anyone else with Visio 16. The only way it would recognize multiple documents open at same time, was to open different documents up within the same Visio session. So I could not go into my file explorer, and locate individual Visio files and open that way. I had to open one file from Start menu, then once that was open, I had to go into File>Open>then select another one to open. It would not open multiple windows, I would have to toggle back and forth between documents, which was fine with me. I accomplished what I was trying to do, and now know what I need to do to make it work. Thanks again!