I have a question about autosave in 2021 pro

I was wondering if Auto save is working I have Auto save selected and set up for 5 minutes. I noticed Auto save did not save my last project and backup did not work it had worked in the past.

The auto save in SketchUp does not auto save your working file. It auto saves a recovery file.

If you are using SketchUp 2019 you can see that recovery file being saved here:

%LocalAppData%\SketchUp\SketchUp 2019\SketchUp\working\SKETCHUP\RecoveredFiles