A prior year tax return can not be done with the online version of the program. You must install the desktop/CD version and use that program to complete your 2015 return. A prior year tax return can not be e-filed. You have to print it, sign it and mail it to the IRS. Get the desktop version of TurboTax 2015 at https://turbotax.intuit.com/personal-taxes/past-years-products/