The current online software is only for 2017 returns. Online preparation and e-filing for 2016 is permanently closed. If you need to prepare a 2016 return:
To file a return for a prior tax year
If you need to prepare a return for 2014, 2015, or 2016 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
https://turbotax.intuit.com/personal-taxes/past-years-products/
Remember to prepare your state return as well—if you live in a state that has a state income tax.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return.
Be sure to clear out whatever you typed into the 2017 online program.
Note: You can clear out the “wrong-year” information that you entered in to the 2017 software and then use the software when you are ready to prepare your 2017 return: