had the same exact problem trying to save my return and it would give an error saying" File not found". I am using Windows 10. I initially got around this by saving the return in my Downloads folder. Later I found several messages in my Notifications (click on the little square with a half moon in the lower right corner of the screen) area regarding protected folder access violation. There were several entries, one for each time I tried to save my return. I just clicked on the notice to pull up the message, found that TurboTax had been denied access several times, clicked on actions Actions/Allow on Device. PROBLEM SOLVED.
