Twice I have started my 2016 Fed Tax Return, and saved it. When I open it later, all of the data is gone, and it says "Hi, Welcome to TurboTax!" What's going on?

I am working on the desktop version, not any web based version. I've gone to File, hit save, named it and put it into my tax folder on my computer. Again, when I go to reopen a couple of days later to continue, it asks me if I want to update; I type yes. After it does the update, it then opens on the welcome screen and asks me if I'm ready to start -- and none of the data I've put in previously is there. Very frustrating; I've already wasted several hours with this program.