We always encourage people to generate two PDF files after they file any year's tax return
1) A filing-only PDF copy, that contains only the forms that would be needed if filing by mail. (even if you efiled)
AND
2) A PDF copy for your records, containing ALL backup forms and worksheets.
AND THEN...back those PDF files up on an off-computer device or cloud storage
If you do that every year, then you don't need the .taxyyyy datafile to see what you entered in your file.
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Of course, if you think you might need to actually process any old tax returns with software, you never uninstall any year's tax program (if using the download software).
At least on Windows systems, the desktop software will continue to work properly as long as they are not uninstalled (I once had ~8yrs of TTX software installed and working)....but when you get a new computer, you can only re-install back ~ 3 years, which is why the PDF files become critical for future reference of what was in them.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
