with the desktop app find the folder that contains the XXXX.tax2021 file. there should be a second file in the folder that has the same name but starts with a tilde ~ . this is a backup. copy it to a new file (in the same folder) with a unique name ending with the extension .tax2021(must have this so your computer knows what program to use to open it). then double click on it with your mouse to open. if it is also corrupt then you are out of luck because Turbotax does not have copies of returns prepared with desktop software. you'll have to start over.
on a windows computer, the folder should be in c:\users\users name\documents\Turbotax
don't know about MACS
