Well, first you need to make absolutely sure it is the 2020 software you installed....but even if it is, on the first startup the 2020 software, it does ask you to look for a 2019 file to transfer-in all of last year's information so you don't have to type everything in again.....but you don't have to select a 2019 file...you can skip that step.
-----------------------
If you have confirmed it is the 2020 software...
1) Copy the .tax2020 datafile onto the new computer's main system hard drive....don't try to load it from the Flash drive.
2) Start a NEW tax file on the new software first...and enter minimal information about you and the state you are a resident of ....to get into it a ways ....then you have to go to the state section and download /install the sate(s) you have in your real 2020 file. You can't open the 2020 file until the sate(s) are installed first. SaveAs that file with a "tempfile" name of some kind.
3) then go to the upper left corner.:
<File <<Open Tax Return (n might have to do that twice) and then you will browse to that 2020 tax file and open it. Once you have saved it at least one time, it will now show up in the opening screen every time you start up teh TTX software (as long as you don't move the file).
__________________________
Final warning though....in past years, many people who did a SaveAs directly to a USB flash drive, found that file was corrupted in some way and wouldn't open, even prepared/opened as I noted above. You may need just take the .tax2020 file that is already there on that other computer's disk....and just copy-paste it to the USB drive...that has always worked...and is also the proper way to back up to a flash drive....never use SaveAs directly to the flash drive.
Of course, maybe yours worked OK...
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
