I think that message is if you try to transfer from the pdf file. Do you have the file ending in .tax2020 on your computer? I assume you are using the Desktop program?
Here's an idea. Do you still have 2020 installed? Try opening 2020 program and see if you can get your 2020 return to show up in it. Go to FILE - OPEN. And see if that is the right one.
Then in the 2020 program do a File-Save AS and give it a easy name you can find or search for. And note where it saves it or select where to save it so you can find it again. The file will end in .tax2020. Then close the 2020 program. Then start a new 2020 return and transfer from the 2020 file.
