Only the TurboTax 2017 desktop software can open the 2017 tax data file which has a file extension of .tax2017.
TurboTax website for prior year desktop software - https://turbotax.intuit.com/personal-taxes/past-years-products/
The 2017 tax data file can be transferred using the 2018 TurboTax desktop editions when a new 2018 tax return is started.
TurboTax website for the 2018 desktop editions - https://turbotax.intuit.com/personal-taxes/cd-download/
Or the 2017 tax data file can be transferred to the 2018 online editions when starting a new 2018 online tax return.
TurboTax website for the 2018 online editions - https://turbotax.intuit.com/personal-taxes/online/
