I didn't use turbo tax online last year, but did use turbo tax on my home computer. Can I upload my 2017 taxes to the online system before I start 2018?

[Carl]

No. However, when you start your return online you will have the option to import from the .tax2017 file on your computer. But you can't "upload" the .tax2017 file to your online account.

[DoninGA]

See this TurboTax support FAQ for transferring the 2017 tax data from the computer to the 2018 online return - https://ttlc.intuit.com/questions/1900883-how-do-i-transfer-last-year-s-return-into-turbotax-online