If you do not have the 2015 program completely installed and updated already since the program is no longer supported which means you cannot get any updates or state programming at this late date.  

Why should I save a PDF copy of my return?

Saving a copy of your return as a PDF (in addition to the proprietary tax data format TurboTax uses) lets you open, view, and print your return using the free Adobe Reader or Foxit Reader software.

This is a lifesaver if your tax data file gets corrupted or if you no longer have the TurboTax software to open it in. The government also accepts a paper-filed return printed from the PDF.

Please note that TurboTax PDF files cannot be "read" by the TurboTax software the way the tax data file can, which means they cannot be used for amending, troubleshooting calculation issues, or for full prior-year transfer capabilities.

If you have old .tax files you can try converting them to pdf files at  Www.Taxprinter.Com 

It might be expensive.  They are not connected with Turbo Tax.  Use it at your own risk.