Can I e-file my 2017 taxes on May 17, 2021?
You absolutely will not be able to do that using TurboTax; paper filing only.
if you are due a refund for 2017, it's too late unless the return was extended. the latest date for filing an unextended 2017 return to get a refund was 5/17/2021. if extended you have until 10/15/2021