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2016 Online to 2017 Downloaded

If you prepared your 2016 return online, in order for your previous year tax information to transfer into your Desktop software you need to download your 2016 Online return as a .tax2016 file.

https://ttlc.intuit.com/questions/1899645-how-do-i-save-my-2015-turbotax-online-return-as-a-tax-data...

If you can't get or didn't save the .tax file to your computer before online was shut down Oct 15 or lost it,  there is a way to do it by starting your return in the 2017 Online version, transfer into that and then you can switch and continue in the desktop version and you won't have to pay for online.  Expand the 3rd section for transferring an Online return in this FAQ
https://ttlc.intuit.com/questions/1901506-transfer-last-year-s-return-into-turbotax-for-windows