You cannot use TurboTax Online to file for 2017. To file for 2017 you have to use the CD or download TurboTax software for 2017. You can purchase a download at the following link. There is no free filing for past years.
The 2017 software will only be available, and supported, for a few more weeks. TurboTax will stop selling it when the 2021 software becomes available.
Tax returns for past years cannot be e-filed. You will have to print your 2017 tax return, sign it, and file it by mail.
You would have to use the Desktop program but I think they just took down 2017. They only sell the last 3 years.
How to prepare a prior year return
Or If you have a simple return You can fill out the blank forms for free.
Here are some blank forms & instructions for 2017
2017 Tax Tables https://www.irs.gov/pub/irs-prior/i1040tt--2017.pdf
Publication 17 Tax Guide for 2017 https://www.irs.gov/pub/irs-prior/p17--2017.pdf
Don’t forget your state. And you will have to print and mail your returns. So be sure to attach copies of your W2s and any 1099s that have withholding on them. You have to mail federal and state in separate envelopes because they go to different places. Get a tracking number from the post office when you mail them for proof of filing.
TurboTax does not support tax year 2017. It is to late to file a 2017 tax return for a tax refund.
If you have taxes owed then you will need to file the 2017 return since penalties and interest are accruing for the unpaid taxes.
You may be able to purchase the 2017 software from a reputable online retailer such as Amazon, Best Buy, Stapes, Walmart, Costco, etc.
Or you will have to find a local tax professional to assist you in completing the 2017 tax return.
The 2017 tax return can only be printed and mailed, it cannot be e-filed.