You must be using the TurboTax 2020 desktop software to open a 2020 tax data file.
If your sister used the TurboTax online editions for the 2020 tax return, you will need to access her online account and down load the 2020 tax data file.
A 2020 tax data file will have a file extension of .tax2020
To open the 2020 tax data file with the 2020 TurboTax software, click on the File menu at the top left of the desktop program screen. Click on Open Tax Return the Browse to the location where the 2020 tax data file as been downloaded and stored.
