The 2017 tax data file, .tax2017, can only be opened by the TurboTax software for 2017.
Go to this TurboTax website for the 2017 desktop software for purchase and download - https://turbotax.intuit.com/personal-taxes/past-years-products/2017
Or download the PDF of the 2017 tax return -
To access your current or prior year online tax returns sign onto the TurboTax website with the userID you used to create the account - https://myturbotax.intuit.com/
Scroll down to the bottom of the screen and on the section Your tax returns & documents click on Show. Click on the Year and Click on Download/print return (PDF)
