Can't download updated version of Sketchup Pro

I just tried to open my SketchUp. Given message that I needed to update to 2020.1. Tried to download. Get an installer that says I have to quit SketchUp in order to proceed. When I quit Sketchup the installer quits. Mac OS

It’s normal that you can’t install an update while an app is running, you have to quit first. But I don’t know why that would cause the installer to quit. Try the installer again when SketchUp is not running.

For some reason, SketchUp was open in the background. I solved the problem by first making sure all applications were closed by restarting. Then I could complete the download