After you file

How to transfer 2017 tax file to the 2018 program -- pick your situation below:

2017 Online to 2018 Online

Simple – just sign in with the same login you used on last year's return and we'll do the rest. Forgot your login?

Note: To transfer last year's return to 2018 Federal Free Edition, you'll need to accept the upgrade to TurboTax PLUS which appears shortly after you sign in.

https://ttlc.intuit.com/questions/1900883-transfer-last-year-s-return-into-turbotax-online

https://ttlc.intuit.com/questions/2776284-why-didn-t-last-year-s-tax-return-transfer-over-in-turbota...

 

2017 Online to 2018 Downloaded

If you prepared your 2017 return online, in order for your previous year tax information to transfer into your Desktop software you need to download your 2017 Online return as a .tax2017 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

2017 Downloaded to 2018 Online

Last year's tax data file (.tax files) can be transferred to Online Deluxe and higher-tier versions.

1.    Sign in to TurboTax Online, if you haven't already done so.

2.    Select Tools on the menu bar lower left on the screen.

3.    In the pop-up window, select Transfer last year's TurboTax return from your computer.

4.    Read the warning and then click Continue (or Cancel to abort the transfer).

5.    Browse to where you saved your .tax2017 file and select it.

6.    Click Transfer Return and wait for your file to finish uploading.

7.    When you see Transfer Complete, click Continue to start working on your return.

https://ttlc.intuit.com/questions/1900883-transfer-last-year-s-return-into-turbotax-online 

 

2017 Downloaded to 2018 Downloaded

Do you have the 2017 tax file on your computer?  It ends in .tax2017.  You need that to transfer into 2018.  First thing you do is start a new return and it should find all your 2017 files and ask if you want to transfer them.  

Here's how for Mac:

https://ttlc.intuit.com/questions/1901265-transfer-last-year-s-return-into-turbotax-for-mac

Here's how for Windows:

 https://ttlc.intuit.com/questions/1901506-transfer-last-year-s-return-into-turbotax-for-windows