Using PE 2024 for first time, have my first project ready for YouTube but won't render/upload. HELP!

Using PE 24 for the first time. Project ready to go but it won't render or upload to ANY destination. In fact the entire screen seems to grey out once I hit the save button and I can't click on anything. What's wrong? As far as I know I'm not doing anything differently to when I had PE 23.