I've spent $60 to upgrade to be able to see my 2017 tax return file, and when I click on it it says that the file can't be opened

[DoninGA]

You need to download the PDF of the 2017 tax return which can be opened by any PDF viewer, such as Adobe Reader - https://get.adobe.com/reader/

If you downloaded the tax data file, which will have a file extension of .tax2017, that file can only be opened by the TurboTax software for tax year 2017 - https://turbotax.intuit.com/personal-taxes/past-years-products/

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/print return (PDF)