Are you using Turbo Tax Business for Windows?
You need to have the file ending in .tax2019 to transfer in to 2020. Are you on Windows? It should be in your Documents then in a Turbo Tax folder. Or search your whole computer for all files ending in .tax or .tax2019. And check your Recycle Bin. Are you on Windows 10? That can move files to different spots like to One Drive. Or to Drop Box. Check your backups. Could it be under a different user on your computer?
If you don't have the main .tax file you might have one that starts with a Tilde sign ~ like "~your name.tax2019". That file is if your computer crashes or your real file gets lost or deleted or corrupt so you can restore it.
See if you have any other .tax2019 files on your computer. Maybe you transferred from the wrong one. Or you changed your return after filing like to test?
Find your Tax file in Windows
https://ttlc.intuit.com/community/tax-data-file/help/find-your-tax-data-file-tax-file-in-windows/00/...
Here's an idea. Do you still have 2019 installed? Try opening 2019 program and see if you can get your 2019 return to show up in it. Go to FILE - OPEN. See if it is the right one. Then save it again with a name and place you can find. Go to File - Save As.
