It should be in your Documents in a Turbo Tax folder. Or search your computer for all files ending in .tax2020. Do you need it to transfer to 2021? If you don't have the main .tax file you might have one that starts with a Tilde sign ~ like "~your name.tax2020". That file is if your computer crashes or your real file gets lost or deleted or corrupt so you can restore it.
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. Then save it again with a name and place you can find. Go to File - Save As. Then start a new 2021return and transfer from the 2020 file.
