Steps to recreate 1) Try to click on save ,then a window will pop up where you need to select which folder you want to save . At this stage close the window (I mean you should not select any folder) then the app crashes.
Speculation: you anticipated the molecules could be moved or/and rolled after saving the model.
If you wan this, you have to leave the edit mode/draw tool symbolized by the pen. Instead, either click on the navigation tool (one button to the left) for rotate/move/zoom of the view. Or click on the index finger icon to eventually drag individual atoms/a selection of atoms while keeping the left mouse button pressed.
I can’t download the video, no. I’m not sure what would lead to a crash, but I can’t reproduce that on my Mac certainly.
Do you have VS C++ on your Windows computer? If so, I would suggest building Avogadro in Debug mode and run an Avogadro through VS debugger to see where the code is crashing.