How do I amend 2017 when all I can get when I follow the TurboTax download instructions is a pdf file and not a .tax file?

[DoninGA]

To access your prior year online tax returns sign onto the TurboTax website with the userID you used to create the account - https://myturbotax.intuit.com/

Scroll down and on the section Your tax returns & documents click on Show.  Click on the Year and Click on Download .tax file

[Pinevalleyite]

I've done that but it only opens on my computer in a pdf. Do I need a special program to be able to get it to open with the .tax file extension?

[DoninGA]

If you downloaded the correct file it will have a file extension of .tax2018 not an extension of .pdf

[DoninGA]

Try this -
When you sign onto your online account and land on the Tax Home web page, scroll down and click on Add a state.  

This will take you back to the 2018 online tax return.
Click on Tax Tools on the left side of the screen.  Click on Tools.  Click on Save your 2018 return to your computer

[fanfare]

you will want to download a .tax2017 file, and yes you will need the 2017 amend program to use the TurboTax procedures.
I believe you can find it online and download it yourself.
Otherwise, contact Support.

[fanfare]

if you have a PDF copy of your original return, you can amend.
It would still require 2017 tax software to prepare your updated correct tax return.