For some reason my revit was working and suddenly stopped showing anything in the 'viewport'? when I reopened it. I opened my DWG on a different computer and it worked fine. I have reinstalled the lastest version of revit (2019) and the same problem occurred. My computer is upto date and definitely has the specifications to run revit. I have attached a photo of what a new file looks like opened on my computer, I can somewhat select objects but only when I click and drag to select multiple (showing as multiple families selected) I don't recall changing any settings from default.
